Merge pull request #22 from FWGS/netsplit

Extended netsplit, network extensions

engine/client/cl_main.c

@@ -65,6 +65,8 @@ convar_t	*cl_showevents;
 convar_t	*cl_cmdrate;
 convar_t	*cl_interp;
 convar_t	*cl_dlmax;
+convar_t	*cl_upmax;
+
 convar_t	*cl_lw;
 convar_t	*cl_charset;
 convar_t	*cl_trace_messages;
@@ -197,12 +199,18 @@ void CL_CheckClientState( void )
 	}
 }
 
-int CL_GetFragmentSize( void *unused )
+int CL_GetFragmentSize( void *unused, fragsize_t mode )
 {
+	if( mode == FRAGSIZE_SPLIT )
+		return 0;
+
+	if( mode == FRAGSIZE_UNRELIABLE )
+		return NET_MAX_MESSAGE;
+
 	if( Netchan_IsLocal( &cls.netchan ))
 		return FRAGMENT_LOCAL_SIZE;
 
-	return FRAGMENT_MIN_SIZE;
+	return cl_upmax->value;
 }
 
 /*
@@ -1017,10 +1025,12 @@ void CL_SendConnectPacket( void )
 	{
 		// set related userinfo keys
 		if( cl_dlmax->value >= 40000 || cl_dlmax->value < 100 )
-			Cvar_FullSet( "cl_maxpacket", "1400", FCVAR_USERINFO );
+			Info_SetValueForKey( cls.userinfo, "cl_maxpacket", "1400", sizeof( cls.userinfo ) );
 		else
-			Cvar_FullSet( "cl_maxpacket", cl_dlmax->string, FCVAR_USERINFO );
-		Cvar_FullSet( "cl_maxpayload", "1000", FCVAR_USERINFO );
+			Info_SetValueForKey( cls.userinfo, "cl_maxpacket", cl_dlmax->string, sizeof( cls.userinfo ) );
+
+		if( !*Info_ValueForKey( cls.userinfo,"cl_maxpayload") )
+			Info_SetValueForKey( cls.userinfo, "cl_maxpayload", "1000", sizeof( cls.userinfo ) );
 
 		/// TODO: add input devices list
 		//Info_SetValueForKey( protinfo, "d", va( "%d", input_devices ), sizeof( protinfo ) );
@@ -1030,17 +1040,24 @@ void CL_SendConnectPacket( void )
 		Info_SetValueForKey( protinfo, "a", Q_buildarch(), sizeof( protinfo ) );
 		Info_SetValueForKey( protinfo, "i", ID_GetMD5(), sizeof( protinfo ) );
 
-		Netchan_OutOfBandPrint( NS_CLIENT, adr, "connect %i %i %i \"%s\" 2 \"%s\"\n",
-			PROTOCOL_LEGACY_VERSION, Q_atoi( qport ), cls.challenge, cls.userinfo, protinfo );
+		Netchan_OutOfBandPrint( NS_CLIENT, adr, "connect %i %i %i \"%s\" %d \"%s\"\n",
+			PROTOCOL_LEGACY_VERSION, Q_atoi( qport ), cls.challenge, cls.userinfo, NET_LEGACY_EXT_SPLIT, protinfo );
 		Con_Printf( "Trying to connect by legacy protocol\n" );
 	}
 	else
 	{
-		// remove useless userinfo keys
-		Cvar_FullSet( "cl_maxpacket", "0", 0 );
-		Cvar_FullSet( "cl_maxpayload", "1000", 0 );
+		int extensions = NET_EXT_SPLITSIZE;
+
+		if( cl_dlmax->value > FRAGMENT_MAX_SIZE  || cl_dlmax->value < FRAGMENT_MIN_SIZE )
+			Cvar_SetValue( "cl_dlmax", FRAGMENT_DEFAULT_SIZE );
+
+		Info_RemoveKey( cls.userinfo,"cl_maxpacket" );
+		Info_RemoveKey( cls.userinfo, "cl_maxpayload" );
+
 		Info_SetValueForKey( protinfo, "uuid", key, sizeof( protinfo ));
 		Info_SetValueForKey( protinfo, "qport", qport, sizeof( protinfo ));
+		Info_SetValueForKey( protinfo, "ext", va("%d", extensions), sizeof( protinfo ));
+
 		Netchan_OutOfBandPrint( NS_CLIENT, adr, "connect %i %i \"%s\" \"%s\"\n", PROTOCOL_VERSION, cls.challenge, protinfo, cls.userinfo );
 		Con_Printf( "Trying to connect by modern protocol\n" );
 	}
@@ -1364,6 +1381,24 @@ void CL_SendDisconnectMessage( void )
 	Netchan_TransmitBits( &cls.netchan, MSG_GetNumBitsWritten( &buf ), MSG_GetData( &buf ));
 }
 
+int CL_GetSplitSize( void )
+{
+	int splitsize;
+
+	if( Host_IsDedicated() )
+		return 0;
+
+	if( !(cls.extensions & NET_EXT_SPLITSIZE) )
+		return 1400;
+
+	splitsize = cl_dlmax->value;
+
+	if( splitsize < FRAGMENT_MIN_SIZE || splitsize > FRAGMENT_MAX_SIZE )
+		Cvar_SetValue( "cl_dlmax", FRAGMENT_DEFAULT_SIZE );
+
+	return cl_dlmax->value;
+}
+
 /*
 =====================
 CL_Reconnect
@@ -1381,13 +1416,22 @@ void CL_Reconnect( qboolean setup_netchan )
 		{
 			unsigned int extensions = Q_atoi( Cmd_Argv( 1 ) );
 
-			if( extensions & NET_EXT_SPLIT )
+			if( extensions & NET_LEGACY_EXT_SPLIT )
 			{
 				// only enable incoming split for legacy mode
 				cls.netchan.split = true;
 				Con_Reportf( "^2NET_EXT_SPLIT enabled^7 (packet sizes is %d/%d)\n", (int)cl_dlmax->value, 65536 );
 			}
 		}
+		else
+		{
+			cls.extensions = Q_atoi( Info_ValueForKey( Cmd_Argv( 1 ), "ext" ));
+
+			if( cls.extensions & NET_EXT_SPLITSIZE )
+			{
+				Con_Reportf( "^2NET_EXT_SPLITSIZE enabled^7 (packet size is %d)\n", (int)cl_dlmax->value );
+			}
+		}
 
 	}
 	else
@@ -1892,7 +1936,7 @@ void CL_ConnectionlessPacket( netadr_t from, sizebuf_t *msg )
 				// too many fails use default connection method
 				Con_Printf( "hi-speed connection is failed, use default method\n" );
 				Netchan_OutOfBandPrint( NS_CLIENT, from, "getchallenge\n" );
-				Cvar_SetValue( "cl_dlmax", FRAGMENT_MIN_SIZE );
+				Cvar_SetValue( "cl_dlmax", FRAGMENT_DEFAULT_SIZE );
 				cls.connect_time = host.realtime;
 				return;
 			}
@@ -2698,7 +2742,8 @@ void CL_InitLocal( void )
 	name = Cvar_Get( "name", Sys_GetCurrentUser(), FCVAR_USERINFO|FCVAR_ARCHIVE|FCVAR_PRINTABLEONLY, "player name" );
 	model = Cvar_Get( "model", "", FCVAR_USERINFO|FCVAR_ARCHIVE, "player model ('player' is a singleplayer model)" );
 	cl_updaterate = Cvar_Get( "cl_updaterate", "20", FCVAR_USERINFO|FCVAR_ARCHIVE, "refresh rate of server messages" );
-	cl_dlmax = Cvar_Get( "cl_dlmax", "0", FCVAR_USERINFO|FCVAR_ARCHIVE, "max allowed fragment size on download resources" );
+	cl_dlmax = Cvar_Get( "cl_dlmax", "0", FCVAR_USERINFO|FCVAR_ARCHIVE, "max allowed outcoming fragment size" );
+	cl_upmax = Cvar_Get( "cl_upmax", "1200", FCVAR_ARCHIVE, "max allowed incoming fragment size" );
 	rate = Cvar_Get( "rate", "3500", FCVAR_USERINFO|FCVAR_ARCHIVE, "player network rate" );
 	topcolor = Cvar_Get( "topcolor", "0", FCVAR_USERINFO|FCVAR_ARCHIVE, "player top color" );
 	bottomcolor = Cvar_Get( "bottomcolor", "0", FCVAR_USERINFO|FCVAR_ARCHIVE, "player bottom color" );
@@ -2708,10 +2753,6 @@ void CL_InitLocal( void )
 	Cvar_Get( "team", "", FCVAR_USERINFO, "player team" );
 	Cvar_Get( "skin", "", FCVAR_USERINFO, "player skin" );
 
-	// legacy mode cvars (need this to add it to userinfo)
-	Cvar_Get( "cl_maxpacket", "0", 0, "legacy server compatibility" );
-	Cvar_Get( "cl_maxpayload", "1000", 0, "legacy server compatibility" );
-
 	cl_showfps = Cvar_Get( "cl_showfps", "1", FCVAR_ARCHIVE, "show client fps" );
 	cl_nosmooth = Cvar_Get( "cl_nosmooth", "0", FCVAR_ARCHIVE, "disable smooth up stair climbing and interpolate position in multiplayer" );
 	cl_smoothtime = Cvar_Get( "cl_smoothtime", "0", FCVAR_ARCHIVE, "time to smooth up" );

engine/client/client.h

@@ -665,6 +665,7 @@ typedef struct
 	netadr_t legacyserver;
 	netadr_t legacyservers[MAX_LEGACY_SERVERS];
 	int	legacyservercount;
+	int extensions;
 } client_static_t;
 
 #ifdef __cplusplus
@@ -778,7 +779,7 @@ void CL_SendCommand( void );
 void CL_Disconnect_f( void );
 void CL_ProcessFile( qboolean successfully_received, const char *filename );
 void CL_WriteUsercmd( sizebuf_t *msg, int from, int to );
-int CL_GetFragmentSize( void *unused );
+int CL_GetFragmentSize( void *unused , fragsize_t mode );
 qboolean CL_PrecacheResources( void );
 void CL_SetupOverviewParams( void );
 void CL_UpdateFrameLerp( void );

engine/common/net_chan.c

@@ -302,7 +302,7 @@ Netchan_Setup
 called to open a channel to a remote system
 ==============
 */
-void Netchan_Setup( netsrc_t sock, netchan_t *chan, netadr_t adr, int qport, void *client, int (*pfnBlockSize)(void * ))
+void Netchan_Setup( netsrc_t sock, netchan_t *chan, netadr_t adr, int qport, void *client, int (*pfnBlockSize)(void *, fragsize_t mode ))
 {
 	Netchan_Clear( chan );
 
@@ -710,7 +710,7 @@ static void Netchan_CreateFragments_( netchan_t *chan, sizebuf_t *msg )
 		return;
 
 	if( chan->pfnBlockSize != NULL )
-		chunksize = chan->pfnBlockSize( chan->client );
+		chunksize = chan->pfnBlockSize( chan->client, FRAGSIZE_FRAG );
 	else chunksize = FRAGMENT_MAX_SIZE; // fallback
 
 	wait = (fragbufwaiting_t *)Mem_Calloc( net_mempool, sizeof( fragbufwaiting_t ));
@@ -871,7 +871,7 @@ void Netchan_CreateFileFragmentsFromBuffer( netchan_t *chan, const char *filenam
 	if( !size ) return;
 
 	if( chan->pfnBlockSize != NULL )
-		chunksize = chan->pfnBlockSize( chan->client );
+		chunksize = chan->pfnBlockSize( chan->client, FRAGSIZE_FRAG );
 	else chunksize = FRAGMENT_MAX_SIZE; // fallback
 
 	if( !LZSS_IsCompressed( pbuf ))
@@ -969,7 +969,7 @@ int Netchan_CreateFileFragments( netchan_t *chan, const char *filename )
 	}
 
 	if( chan->pfnBlockSize != NULL )
-		chunksize = chan->pfnBlockSize( chan->client );
+		chunksize = chan->pfnBlockSize( chan->client, FRAGSIZE_FRAG );
 	else chunksize = FRAGMENT_MAX_SIZE; // fallback
 
 	Q_strncpy( compressedfilename, filename, sizeof( compressedfilename ));
@@ -1458,9 +1458,15 @@ void Netchan_TransmitBits( netchan_t *chan, int length, byte *data )
 		if( send_from_regular && ( send_from_frag[FRAG_NORMAL_STREAM] ))
 		{	
 			send_from_regular = false;
+			int maxsize = MAX_RELIABLE_PAYLOAD;
+
+			if( chan->pfnBlockSize )
+				maxsize = chan->pfnBlockSize( chan->client, FRAGSIZE_SPLIT );
+			if( maxsize == 0 )
+				maxsize = MAX_RELIABLE_PAYLOAD;
 
 			// if the reliable buffer has gotten too big, queue it at the end of everything and clear out buffer
-			if( MSG_GetNumBytesWritten( &chan->message ) > MAX_RELIABLE_PAYLOAD )
+			if( MSG_GetNumBytesWritten( &chan->message ) + (((uint)length) >> 3) > maxsize )
 			{
 				Netchan_CreateFragments_( chan, &chan->message );
 				MSG_Clear( &chan->message );
@@ -1627,9 +1633,16 @@ void Netchan_TransmitBits( netchan_t *chan, int length, byte *data )
 		chan->last_reliable_sequence = chan->outgoing_sequence - 1;
 	}
 
-	if( MSG_GetNumBitsLeft( &send ) >= length )
-		MSG_WriteBits( &send, data, length );
-	else Con_Printf( S_WARN "Netchan_Transmit: unreliable message overflow\n" );
+	if( length )
+	{
+		int maxsize = NET_MAX_MESSAGE;
+		if( chan->pfnBlockSize )
+			maxsize = chan->pfnBlockSize( chan->client, FRAGSIZE_UNRELIABLE );
+
+		if( MSG_GetNumBytesWritten( &send ) + length >> 3 <= maxsize )
+			MSG_WriteBits( &send, data, length );
+		else Con_Printf( S_WARN "Netchan_Transmit: unreliable message overflow: %d\n", MSG_GetNumBytesWritten( &send ) );
+	}
 
 	// deal with packets that are too small for some networks
 	if( MSG_GetNumBytesWritten( &send ) < 16 && !NET_IsLocalAddress( chan->remote_address )) // packet too small for some networks
@@ -1658,7 +1671,10 @@ void Netchan_TransmitBits( netchan_t *chan, int length, byte *data )
 	// send the datagram
 	if( !CL_IsPlaybackDemo( ))
 	{
-		NET_SendPacket( chan->sock, MSG_GetNumBytesWritten( &send ), MSG_GetData( &send ), chan->remote_address );
+		int splitsize = 0;
+		if( chan->pfnBlockSize )
+			splitsize = chan->pfnBlockSize( chan->client, FRAGSIZE_SPLIT );
+		NET_SendPacketEx( chan->sock, MSG_GetNumBytesWritten( &send ), MSG_GetData( &send ), chan->remote_address, splitsize );
 	}
 
 	if( SV_Active() && sv_lan.value && sv_lan_rate.value > 1000.0 )

engine/common/net_ws.c

@@ -35,15 +35,16 @@ GNU General Public License for more details.
 #include "netchan.h"
 #include "mathlib.h"
 
-// #define NET_USE_FRAGMENTS
+#define NET_USE_FRAGMENTS
 
 #define PORT_ANY			-1
 #define MAX_LOOPBACK		4
 #define MASK_LOOPBACK		(MAX_LOOPBACK - 1)
 
 #define MAX_ROUTEABLE_PACKET		1400
-#define SPLIT_SIZE			( MAX_ROUTEABLE_PACKET - sizeof( SPLITPACKET ))
-#define NET_MAX_FRAGMENTS		( NET_MAX_FRAGMENT / SPLIT_SIZE )
+#define	SPLITPACKET_MIN_SIZE			508		// RFC 791: 576(min ip packet) - 60 (ip header) - 8 (udp header)
+#define SPLITPACKET_MAX_SIZE			64000
+#define NET_MAX_FRAGMENTS		( NET_MAX_FRAGMENT / (SPLITPACKET_MIN_SIZE - sizeof( SPLITPACKET )) )
 
 #ifndef _WIN32 // it seems we need to use WS2 to support it
 #define HAVE_GETADDRINFO
@@ -1105,13 +1106,17 @@ NET_GetLong
 receive long packet from network
 ==================
 */
-qboolean NET_GetLong( byte *pData, int size, int *outSize )
+qboolean NET_GetLong( byte *pData, int size, int *outSize, int splitsize )
 {
 	int		i, sequence_number, offset;
 	SPLITPACKET	*pHeader = (SPLITPACKET *)pData;
 	int		packet_number;
 	int		packet_count;
 	short		packet_id;
+	int body_size = splitsize - sizeof( SPLITPACKET );
+
+	if( body_size < 0 )
+		return false;
 
 	if( size < sizeof( SPLITPACKET ))
 	{
@@ -1149,7 +1154,7 @@ qboolean NET_GetLong( byte *pData, int size, int *outSize )
 	if( net.split_flags[packet_number] != sequence_number )
 	{
 		if( packet_number == ( packet_count - 1 ))
-			net.split.total_size = size + SPLIT_SIZE * ( packet_count - 1 );
+			net.split.total_size = size + body_size * ( packet_count - 1 );
 
 		net.split.split_count--;
 		net.split_flags[packet_number] = sequence_number;
@@ -1162,7 +1167,7 @@ qboolean NET_GetLong( byte *pData, int size, int *outSize )
 		Con_DPrintf( "NET_GetLong: Ignoring duplicated split packet %i of %i ( %i bytes )\n", packet_number + 1, packet_count, size );
 	}
 
-	offset = (packet_number * SPLIT_SIZE);
+	offset = (packet_number * body_size);
 	memcpy( net.split.buffer + offset, pData + sizeof( SPLITPACKET ), size );
 
 	// have we received all of the pieces to the packet?
@@ -1221,13 +1226,13 @@ qboolean NET_QueuePacket( netsrc_t sock, netadr_t *from, byte *data, size_t *len
 #ifndef XASH_DEDICATED
 				if( CL_LegacyMode() )
 					return NET_LagPacket( true, sock, from, length, data );
-#endif
+
 				// check for split message
-				if( *(int *)data == NET_HEADER_SPLITPACKET )
+				if( sock == NS_CLIENT && *(int *)data == NET_HEADER_SPLITPACKET )
 				{
-					return NET_GetLong( data, ret, length );
+					return NET_GetLong( data, ret, length, CL_GetSplitSize() );
 				}
-
+#endif
 				// lag the packet, if needed
 				return NET_LagPacket( true, sock, from, length, data );
 			}
@@ -1288,15 +1293,16 @@ NET_SendLong
 Fragment long packets, send short directly
 ==================
 */
-int NET_SendLong( netsrc_t sock, int net_socket, const char *buf, int len, int flags, const struct sockaddr *to, int tolen )
+int NET_SendLong( netsrc_t sock, int net_socket, const char *buf, size_t len, int flags, const struct sockaddr *to, size_t tolen, size_t splitsize )
 {
 #ifdef NET_USE_FRAGMENTS
 	// do we need to break this packet up?
-	if( sock == NS_SERVER && len > MAX_ROUTEABLE_PACKET )
+	if( splitsize > sizeof( SPLITPACKET ) && sock == NS_SERVER && len > splitsize )
 	{
-		char		packet[MAX_ROUTEABLE_PACKET];
+		char		packet[SPLITPACKET_MAX_SIZE];
 		int		total_sent, size, packet_count;
 		int		ret, packet_number;
+		int body_size = splitsize - sizeof( SPLITPACKET );
 		SPLITPACKET	*pPacket;
 
 		net.sequence_number++;
@@ -1308,13 +1314,13 @@ int NET_SendLong( netsrc_t sock, int net_socket, const char *buf, int len, int f
 		pPacket->net_id = NET_HEADER_SPLITPACKET;
 		packet_number = 0;
 		total_sent = 0;
-		packet_count = (len + SPLIT_SIZE - 1) / SPLIT_SIZE;
+		packet_count = (len + body_size - 1) / body_size;
 
 		while( len > 0 )
 		{
-			size = Q_min( SPLIT_SIZE, len );
+			size = Q_min( body_size, len );
 			pPacket->packet_id = (packet_number << 8) + packet_count;
-			memcpy( packet + sizeof( SPLITPACKET ), buf + ( packet_number * SPLIT_SIZE ), size );
+			memcpy( packet + sizeof( SPLITPACKET ), buf + ( packet_number * body_size ), size );
 
 			if( net_showpackets && net_showpackets->value == 3.0f )
 			{
@@ -1349,10 +1355,10 @@ int NET_SendLong( netsrc_t sock, int net_socket, const char *buf, int len, int f
 
 /*
 ==================
-NET_SendPacket
+NET_SendPacketEx
 ==================
 */
-void NET_SendPacket( netsrc_t sock, size_t length, const void *data, netadr_t to )
+void NET_SendPacketEx( netsrc_t sock, size_t length, const void *data, netadr_t to, size_t splitsize )
 {
 	int		ret;
 	struct sockaddr	addr;
@@ -1382,7 +1388,7 @@ void NET_SendPacket( netsrc_t sock, size_t length, const void *data, netadr_t to
 
 	NET_NetadrToSockadr( &to, &addr );
 
-	ret = NET_SendLong( sock, net_socket, data, length, 0, &addr, sizeof( addr ));
+	ret = NET_SendLong( sock, net_socket, data, length, 0, &addr, sizeof( addr ), splitsize );
 
 	if( NET_IsSocketError( ret ))
 	{
@@ -1412,6 +1418,16 @@ void NET_SendPacket( netsrc_t sock, size_t length, const void *data, netadr_t to
 
 }
 
+/*
+==================
+NET_SendPacket
+==================
+*/
+void NET_SendPacket( netsrc_t sock, size_t length, const void *data, netadr_t to )
+{
+	return NET_SendPacketEx( sock, length, data, to, 0 );
+}
+
 /*
 ====================
 NET_BufferToBufferCompress

engine/common/net_ws.h

@@ -61,10 +61,12 @@ qboolean NET_GetPacket( netsrc_t sock, netadr_t *from, byte *data, size_t *lengt
 qboolean NET_BufferToBufferCompress( char *dest, uint *destLen, char *source, uint sourceLen );
 qboolean NET_BufferToBufferDecompress( char *dest, uint *destLen, char *source, uint sourceLen );
 void NET_SendPacket( netsrc_t sock, size_t length, const void *data, netadr_t to );
+void NET_SendPacketEx( netsrc_t sock, size_t length, const void *data, netadr_t to, size_t splitsize );
 void NET_ClearLagData( qboolean bClient, qboolean bServer );
 
 #ifndef XASH_DEDICATED
 qboolean CL_LegacyMode( void );
+int CL_GetSplitSize( void );
 #endif
 
 void HTTP_AddCustomServer( const char *url );

engine/common/netchan.h

@@ -59,10 +59,10 @@ GNU General Public License for more details.
 // {
 //  byte (on/off)
 //  int (fragment id)
-//  short (startpos)
-//  short (length)
+//  int (startpos)
+//  int (length)
 // }
-#define HEADER_BYTES		( 8 + MAX_STREAMS * 9 )
+#define HEADER_BYTES		( 8 + MAX_STREAMS * 13 )
 
 // Pad this to next higher 16 byte boundary
 // This is the largest packet that can come in/out over the wire, before processing the header
@@ -84,7 +84,7 @@ GNU General Public License for more details.
 #define NUM_PACKET_ENTITIES		256	// 170 Mb for multiplayer with 32 players
 #define MAX_CUSTOM_BASELINES		64
 
-#define NET_EXT_SPLIT		(1U<<1)
+#define NET_LEGACY_EXT_SPLIT		(1U<<1)
 #define NETSPLIT_BACKUP 8
 #define NETSPLIT_BACKUP_MASK (NETSPLIT_BACKUP - 1)
 #define NETSPLIT_HEADER_SIZE 18
@@ -182,6 +182,13 @@ typedef struct fbufqueue_s
 	fragbuf_t		*fragbufs;	// the actual buffers
 } fragbufwaiting_t;
 
+typedef enum fragsize_e
+{
+	FRAGSIZE_FRAG,
+	FRAGSIZE_SPLIT,
+	FRAGSIZE_UNRELIABLE
+} fragsize_t;
+
 // Network Connection Channel
 typedef struct netchan_s
 {
@@ -205,7 +212,7 @@ typedef struct netchan_s
 
 	// callback to get actual framgment size
 	void		*client;
-	int (*pfnBlockSize)( void *cl );
+	int (*pfnBlockSize)( void *cl, fragsize_t mode );
 
 	// staging and holding areas
 	sizebuf_t		message;
@@ -261,7 +268,7 @@ extern int		net_drop;
 
 void Netchan_Init( void );
 void Netchan_Shutdown( void );
-void Netchan_Setup( netsrc_t sock, netchan_t *chan, netadr_t adr, int qport, void *client, int (*pfnBlockSize)(void * ) );
+void Netchan_Setup( netsrc_t sock, netchan_t *chan, netadr_t adr, int qport, void *client, int (*pfnBlockSize)(void *, fragsize_t mode ) );
 void Netchan_CreateFileFragmentsFromBuffer( netchan_t *chan, const char *filename, byte *pbuf, int size );
 qboolean Netchan_CopyNormalFragments( netchan_t *chan, sizebuf_t *msg, size_t *length );
 qboolean Netchan_CopyFileFragments( netchan_t *chan, sizebuf_t *msg );

engine/common/protocol.h

@@ -174,8 +174,8 @@ GNU General Public License for more details.
 
 #define MAX_RESOURCES		(MAX_MODELS+MAX_SOUNDS+MAX_CUSTOM+MAX_EVENTS)
 #define MAX_RESOURCE_BITS		13	// 13 bits 8192 resource (4096 models + 2048 sounds + 1024 events + 1024 files)
-
-#define FRAGMENT_MIN_SIZE		1200		// default MTU
+#define	FRAGMENT_MIN_SIZE			508		// RFC 791: 576(min ip packet) - 60 (ip header) - 8 (udp header)
+#define FRAGMENT_DEFAULT_SIZE		1200		// default MTU
 #define FRAGMENT_MAX_SIZE		64000		// maximal fragment size
 #define FRAGMENT_LOCAL_SIZE		FRAGMENT_MAX_SIZE	// local connection
 
@@ -243,6 +243,9 @@ GNU General Public License for more details.
 extern const char	*svc_strings[svc_lastmsg+1];
 extern const char	*clc_strings[clc_lastmsg+1];
 
+// FWGS extensions
+#define NET_EXT_SPLITSIZE (1U<<0) // set splitsize by cl_dlmax
+
 // legacy protocol definitons
 #define PROTOCOL_LEGACY_VERSION		48
 #define svc_legacy_modelindex		31	// [index][modelpath]

engine/server/server.h

@@ -252,6 +252,7 @@ typedef struct sv_client_s
 
 	int		challenge;		// challenge of this user, randomly generated
 	int		userid;			// identifying number on server
+	int		extensions;
 } sv_client_t;
 
 /*

engine/server/sv_client.c

@@ -87,7 +87,7 @@ void SV_GetChallenge( netadr_t from )
 	Netchan_OutOfBandPrint( NS_SERVER, svs.challenges[i].adr, "challenge %i", svs.challenges[i].challenge );
 }
 
-int SV_GetFragmentSize( void *pcl )
+int SV_GetFragmentSize( void *pcl, fragsize_t mode )
 {
 	sv_client_t *cl = (sv_client_t*)pcl;
 	int	cl_frag_size;
@@ -95,10 +95,39 @@ int SV_GetFragmentSize( void *pcl )
 	if( Netchan_IsLocal( &cl->netchan ))
 		return FRAGMENT_LOCAL_SIZE;
 
+	if( mode == FRAGSIZE_UNRELIABLE )
+	{
+		// allow setting unreliable limit with "setinfo cl_urmax"
+		cl_frag_size = Q_atoi( Info_ValueForKey( cl->userinfo, "cl_urmax" ));
+		if( cl_frag_size == 0 )
+			return NET_MAX_MESSAGE;
+		return bound( FRAGMENT_MAX_SIZE, cl_frag_size, NET_MAX_MESSAGE );
+	}
+
 	cl_frag_size = Q_atoi( Info_ValueForKey( cl->userinfo, "cl_dlmax" ));
 	cl_frag_size = bound( FRAGMENT_MIN_SIZE, cl_frag_size, FRAGMENT_MAX_SIZE );
 
-	return cl_frag_size;
+	if( mode != FRAGSIZE_FRAG )
+	{
+		if( cl->extensions & NET_EXT_SPLITSIZE )
+			return cl_frag_size;
+		else
+			return 0; // original engine behaviour
+	}
+
+	// get in-game fragmentation size
+	if( cl->state == cs_spawned )
+	{
+		// allow setting in-game fragsize with "setinfo cl_frmax"
+		int frmax = Q_atoi( Info_ValueForKey( cl->userinfo, "cl_frmax" ));
+
+		if( frmax < FRAGMENT_MIN_SIZE || frmax > FRAGMENT_MAX_SIZE )
+			cl_frag_size = frmax;
+		else
+			cl_frag_size /= 2;// add window for unreliable
+	}
+
+	return cl_frag_size - HEADER_BYTES;
 }
 
 /*
@@ -242,6 +271,7 @@ void SV_ConnectClient( netadr_t from )
 	int		i, count = 0;
 	int		challenge;
 	const char		*s;
+	int extensions;
 
 	if( Cmd_Argc() < 5 )
 	{
@@ -283,6 +313,9 @@ void SV_ConnectClient( netadr_t from )
 		return;
 	}
 
+	extensions = Q_atoi( Info_ValueForKey( protinfo, "ext" ) );
+
+
 	// LAN servers restrict to class b IP addresses
 	if( !SV_CheckIPRestrictions( from ))
 	{
@@ -346,6 +379,7 @@ void SV_ConnectClient( netadr_t from )
 	newcl->frames = (client_frame_t *)Z_Calloc( sizeof( client_frame_t ) * SV_UPDATE_BACKUP );
 	newcl->userid = g_userid++;	// create unique userid
 	newcl->state = cs_connected;
+	newcl->extensions = extensions & (NET_EXT_SPLITSIZE);
 
 	// reset viewentities (from previous level)
 	memset( newcl->viewentity, 0, sizeof( newcl->viewentity ));
@@ -356,8 +390,15 @@ void SV_ConnectClient( netadr_t from )
 	Netchan_Setup( NS_SERVER, &newcl->netchan, from, qport, newcl, SV_GetFragmentSize );
 	MSG_Init( &newcl->datagram, "Datagram", newcl->datagram_buf, sizeof( newcl->datagram_buf )); // datagram buf
 
+	Q_strncpy( newcl->hashedcdkey, Info_ValueForKey( protinfo, "uuid" ), 32 );
+	newcl->hashedcdkey[32] = '\0';
+
+	// build protinfo answer
+	protinfo[0] = '\0';
+	Info_SetValueForKey( protinfo, "ext", va( "%d",newcl->extensions ), sizeof( protinfo ) );
+
 	// send the connect packet to the client
-	Netchan_OutOfBandPrint( NS_SERVER, from, "client_connect" );
+	Netchan_OutOfBandPrint( NS_SERVER, from, "client_connect %s", protinfo );
 
 	newcl->upstate = us_inactive;
 	newcl->connection_started = host.realtime;
@@ -365,8 +406,7 @@ void SV_ConnectClient( netadr_t from )
 	newcl->delta_sequence = -1;
 	newcl->flags = 0;
 
-	Q_strncpy( newcl->hashedcdkey, Info_ValueForKey( protinfo, "uuid" ), 32 );
-	newcl->hashedcdkey[32] = '\0';
+
 
 	// reset any remaining events
 	memset( &newcl->events, 0, sizeof( newcl->events ));