path: root/src/server/sv_main.c

/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.
Copyright (C) 2000-2006 Tim Angus

This file is part of Tremulous.

Tremulous is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.

Tremulous is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Tremulous; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/

#include "server.h"

serverStatic_t	svs;				// persistant server info
server_t		sv;					// local server
vm_t			*gvm = NULL;				// game virtual machine // bk001212 init

cvar_t	*sv_fps;				// time rate for running non-clients
cvar_t	*sv_timeout;			// seconds without any message
cvar_t	*sv_zombietime;			// seconds to sink messages after disconnect
cvar_t	*sv_rconPassword;		// password for remote server commands
cvar_t	*sv_privatePassword;	// password for the privateClient slots
cvar_t	*sv_allowDownload;
cvar_t	*sv_maxclients;

cvar_t	*sv_privateClients;		// number of clients reserved for password
cvar_t	*sv_hostname;
cvar_t	*sv_master[MAX_MASTER_SERVERS];		// master server ip address
cvar_t	*sv_reconnectlimit;		// minimum seconds between connect messages
cvar_t	*sv_showloss;			// report when usercmds are lost
cvar_t	*sv_padPackets;			// add nop bytes to messages
cvar_t	*sv_killserver;			// menu system can set to 1 to shut server down
cvar_t	*sv_mapname;
cvar_t	*sv_mapChecksum;
cvar_t	*sv_serverid;
cvar_t	*sv_maxRate;
cvar_t	*sv_minPing;
cvar_t	*sv_maxPing;
cvar_t	*sv_pure;
cvar_t	*sv_lanForceRate; // dedicated 1 (LAN) server forces local client rates to 99999 (bug #491)

/*
=============================================================================

EVENT MESSAGES

=============================================================================
*/

/*
===============
SV_ExpandNewlines

Converts newlines to "\n" so a line prints nicer
===============
*/
char	*SV_ExpandNewlines( char *in ) {
	static	char	string[1024];
	int		l;

	l = 0;
	while ( *in && l < sizeof(string) - 3 ) {
		if ( *in == '\n' ) {
			string[l++] = '\\';
			string[l++] = 'n';
		} else {
			string[l++] = *in;
		}
		in++;
	}
	string[l] = 0;

	return string;
}

/*
======================
SV_ReplacePendingServerCommands

  This is ugly
======================
*/
int SV_ReplacePendingServerCommands( client_t *client, const char *cmd ) {
	int i, index, csnum1, csnum2;

	for ( i = client->reliableSent+1; i <= client->reliableSequence; i++ ) {
		index = i & ( MAX_RELIABLE_COMMANDS - 1 );
		//
		if ( !Q_strncmp(cmd, client->reliableCommands[ index ], strlen("cs")) ) {
			sscanf(cmd, "cs %i", &csnum1);
			sscanf(client->reliableCommands[ index ], "cs %i", &csnum2);
			if ( csnum1 == csnum2 ) {
				Q_strncpyz( client->reliableCommands[ index ], cmd, sizeof( client->reliableCommands[ index ] ) );
				/*
				if ( client->netchan.remoteAddress.type != NA_BOT ) {
					Com_Printf( "WARNING: client %i removed double pending config string %i: %s\n", client-svs.clients, csnum1, cmd );
				}
				*/
				return qtrue;
			}
		}
	}
	return qfalse;
}

/*
======================
SV_AddServerCommand

The given command will be transmitted to the client, and is guaranteed to
not have future snapshot_t executed before it is executed
======================
*/
void SV_AddServerCommand( client_t *client, const char *cmd ) {
	int		index, i;

	// this is very ugly but it's also a waste to for instance send multiple config string updates
	// for the same config string index in one snapshot
//	if ( SV_ReplacePendingServerCommands( client, cmd ) ) {
//		return;
//	}

	client->reliableSequence++;
	// if we would be losing an old command that hasn't been acknowledged,
	// we must drop the connection
	// we check == instead of >= so a broadcast print added by SV_DropClient()
	// doesn't cause a recursive drop client
	if ( client->reliableSequence - client->reliableAcknowledge == MAX_RELIABLE_COMMANDS + 1 ) {
		Com_Printf( "===== pending server commands =====\n" );
		for ( i = client->reliableAcknowledge + 1 ; i <= client->reliableSequence ; i++ ) {
			Com_Printf( "cmd %5d: %s\n", i, client->reliableCommands[ i & (MAX_RELIABLE_COMMANDS-1) ] );
		}
		Com_Printf( "cmd %5d: %s\n", i, cmd );
		SV_DropClient( client, "Server command overflow" );
		return;
	}
	index = client->reliableSequence & ( MAX_RELIABLE_COMMANDS - 1 );
	Q_strncpyz( client->reliableCommands[ index ], cmd, sizeof( client->reliableCommands[ index ] ) );
}


/*
=================
SV_SendServerCommand

Sends a reliable command string to be interpreted by 
the client game module: "cp", "print", "chat", etc
A NULL client will broadcast to all clients
=================
*/
void QDECL SV_SendServerCommand(client_t *cl, const char *fmt, ...) {
	va_list		argptr;
	byte		message[MAX_MSGLEN];
	client_t	*client;
	int			j;
	
	va_start (argptr,fmt);
	Q_vsnprintf ((char *)message, sizeof(message), fmt,argptr);
	va_end (argptr);

	// Fix to http://aluigi.altervista.org/adv/q3msgboom-adv.txt
	// The actual cause of the bug is probably further downstream
	// and should maybe be addressed later, but this certainly
	// fixes the problem for now
	if ( strlen ((char *)message) > 1022 ) {
		return;
	}

	if ( cl != NULL ) {
		SV_AddServerCommand( cl, (char *)message );
		return;
	}

	// hack to echo broadcast prints to console
	if ( com_dedicated->integer && !strncmp( (char *)message, "print", 5) ) {
		Com_Printf ("broadcast: %s\n", SV_ExpandNewlines((char *)message) );
	}

	// send the data to all relevent clients
	for (j = 0, client = svs.clients; j < sv_maxclients->integer ; j++, client++) {
		if ( client->state < CS_PRIMED ) {
			continue;
		}
		SV_AddServerCommand( client, (char *)message );
	}
}


/*
==============================================================================

MASTER SERVER FUNCTIONS

==============================================================================
*/

/*
================
SV_MasterHeartbeat

Send a message to the masters every few minutes to
let it know we are alive, and log information.
We will also have a heartbeat sent when a server
changes from empty to non-empty, and full to non-full,
but not on every player enter or exit.
================
*/
#define	HEARTBEAT_MSEC	300*1000
#define	HEARTBEAT_GAME	"Tremulous"
void SV_MasterHeartbeat( void ) {
	static netadr_t	adr[MAX_MASTER_SERVERS];
	int			i;

	// "dedicated 1" is for lan play, "dedicated 2" is for inet public play
	if ( !com_dedicated || com_dedicated->integer != 2 ) {
		return;		// only dedicated servers send heartbeats
	}

	// if not time yet, don't send anything
	if ( svs.time < svs.nextHeartbeatTime ) {
		return;
	}
	svs.nextHeartbeatTime = svs.time + HEARTBEAT_MSEC;


	// send to group masters
	for ( i = 0 ; i < MAX_MASTER_SERVERS ; i++ ) {
		if ( !sv_master[i]->string[0] ) {
			continue;
		}

		// see if we haven't already resolved the name
		// resolving usually causes hitches on win95, so only
		// do it when needed
		if ( sv_master[i]->modified ) {
			sv_master[i]->modified = qfalse;
	
			Com_Printf( "Resolving %s\n", sv_master[i]->string );
			if ( !NET_StringToAdr( sv_master[i]->string, &adr[i] ) ) {
				// if the address failed to resolve, clear it
				// so we don't take repeated dns hits
				Com_Printf( "Couldn't resolve address: %s\n", sv_master[i]->string );
				Cvar_Set( sv_master[i]->name, "" );
				sv_master[i]->modified = qfalse;
				continue;
			}
			if ( !strstr( ":", sv_master[i]->string ) ) {
				adr[i].port = BigShort( PORT_MASTER );
			}
			Com_Printf( "%s resolved to %i.%i.%i.%i:%i\n", sv_master[i]->string,
				adr[i].ip[0], adr[i].ip[1], adr[i].ip[2], adr[i].ip[3],
				BigShort( adr[i].port ) );
		}


		Com_Printf ("Sending heartbeat to %s\n", sv_master[i]->string );
		// this command should be changed if the server info / status format
		// ever incompatably changes
		NET_OutOfBandPrint( NS_SERVER, adr[i], "heartbeat %s\n", HEARTBEAT_GAME );
	}
}

/*
=================
SV_MasterShutdown

Informs all masters that this server is going down
=================
*/
void SV_MasterShutdown( void ) {
	// send a hearbeat right now
	svs.nextHeartbeatTime = -9999;
	SV_MasterHeartbeat();

	// send it again to minimize chance of drops
	svs.nextHeartbeatTime = -9999;
	SV_MasterHeartbeat();

	// when the master tries to poll the server, it won't respond, so
	// it will be removed from the list
}

/*
=================
SV_MasterGameStat
=================
*/
void SV_MasterGameStat( const char *data )
{
	static netadr_t	adr;

	if( !com_dedicated || com_dedicated->integer != 2 )
		return;		// only dedicated servers send stats

  Com_Printf( "Resolving %s\n", MASTER_SERVER_NAME );
  if( !NET_StringToAdr( MASTER_SERVER_NAME, &adr ) )
  {
    Com_Printf( "Couldn't resolve address: %s\n", MASTER_SERVER_NAME );
    return;
  }
  else
  {
    if( !strstr( ":", MASTER_SERVER_NAME ) )
      adr.port = BigShort( PORT_MASTER );

    Com_Printf( "%s resolved to %i.%i.%i.%i:%i\n", MASTER_SERVER_NAME,
      adr.ip[0], adr.ip[1], adr.ip[2], adr.ip[3],
      BigShort( adr.port ) );
  }

  Com_Printf ("Sending gamestat to %s\n", MASTER_SERVER_NAME );
  NET_OutOfBandPrint( NS_SERVER, adr, "gamestat %s", data );
}

/*
==============================================================================

CONNECTIONLESS COMMANDS

==============================================================================
*/

/*
================
SVC_Status

Responds with all the info that qplug or qspy can see about the server
and all connected players.  Used for getting detailed information after
the simple info query.
================
*/
void SVC_Status( netadr_t from ) {
	char	player[1024];
	char	status[MAX_MSGLEN];
	int		i;
	client_t	*cl;
	playerState_t	*ps;
	int		statusLength;
	int		playerLength;
	char	infostring[MAX_INFO_STRING];

	strcpy( infostring, Cvar_InfoString( CVAR_SERVERINFO ) );

	// echo back the parameter to status. so master servers can use it as a challenge
	// to prevent timed spoofed reply packets that add ghost servers
	Info_SetValueForKey( infostring, "challenge", Cmd_Argv(1) );

	// add "demo" to the sv_keywords if restricted
	if ( Cvar_VariableValue( "fs_restrict" ) ) {
		char	keywords[MAX_INFO_STRING];

		Com_sprintf( keywords, sizeof( keywords ), "demo %s",
			Info_ValueForKey( infostring, "sv_keywords" ) );
		Info_SetValueForKey( infostring, "sv_keywords", keywords );
	}

	status[0] = 0;
	statusLength = 0;

	for (i=0 ; i < sv_maxclients->integer ; i++) {
		cl = &svs.clients[i];
		if ( cl->state >= CS_CONNECTED ) {
			ps = SV_GameClientNum( i );
			Com_sprintf (player, sizeof(player), "%i %i \"%s\"\n", 
				ps->persistant[PERS_SCORE], cl->ping, cl->name);
			playerLength = strlen(player);
			if (statusLength + playerLength >= sizeof(status) ) {
				break;		// can't hold any more
			}
			strcpy (status + statusLength, player);
			statusLength += playerLength;
		}
	}

	NET_OutOfBandPrint( NS_SERVER, from, "statusResponse\n%s\n%s", infostring, status );
}

/*
================
SVC_Info

Responds with a short info message that should be enough to determine
if a user is interested in a server to do a full status
================
*/
void SVC_Info( netadr_t from ) {
	int		i, count;
	char	*gamedir;
	char	infostring[MAX_INFO_STRING];

	/*
	 * Check whether Cmd_Argv(1) has a sane length. This was not done in the original Quake3 version which led
	 * to the Infostring bug discovered by Luigi Auriemma. See http://aluigi.altervista.org/ for the advisory.
	 */

	// A maximum challenge length of 128 should be more than plenty.
	if(strlen(Cmd_Argv(1)) > 128)
		return;

	// don't count privateclients
	count = 0;
	for ( i = sv_privateClients->integer ; i < sv_maxclients->integer ; i++ ) {
		if ( svs.clients[i].state >= CS_CONNECTED ) {
			count++;
		}
	}

	infostring[0] = 0;

	// echo back the parameter to status. so servers can use it as a challenge
	// to prevent timed spoofed reply packets that add ghost servers
	Info_SetValueForKey( infostring, "challenge", Cmd_Argv(1) );

	Info_SetValueForKey( infostring, "protocol", va("%i", PROTOCOL_VERSION) );
	Info_SetValueForKey( infostring, "hostname", sv_hostname->string );
	Info_SetValueForKey( infostring, "mapname", sv_mapname->string );
	Info_SetValueForKey( infostring, "clients", va("%i", count) );
	Info_SetValueForKey( infostring, "sv_maxclients", 
		va("%i", sv_maxclients->integer - sv_privateClients->integer ) );
	Info_SetValueForKey( infostring, "pure", va("%i", sv_pure->integer ) );

	if( sv_minPing->integer ) {
		Info_SetValueForKey( infostring, "minPing", va("%i", sv_minPing->integer) );
	}
	if( sv_maxPing->integer ) {
		Info_SetValueForKey( infostring, "maxPing", va("%i", sv_maxPing->integer) );
	}
	gamedir = Cvar_VariableString( "fs_game" );
	if( *gamedir ) {
		Info_SetValueForKey( infostring, "game", gamedir );
	}

	NET_OutOfBandPrint( NS_SERVER, from, "infoResponse\n%s", infostring );
}

/*
================
SVC_FlushRedirect

================
*/
void SV_FlushRedirect( char *outputbuf ) {
	NET_OutOfBandPrint( NS_SERVER, svs.redirectAddress, "print\n%s", outputbuf );
}

/*
===============
SVC_RemoteCommand

An rcon packet arrived from the network.
Shift down the remaining args
Redirect all printfs
===============
*/
void SVC_RemoteCommand( netadr_t from, msg_t *msg ) {
	qboolean	valid;
	unsigned int time;
	char		remaining[1024];
	// TTimo - scaled down to accumulate, but not overflow anything network wise, print wise etc.
	// (OOB messages are the bottleneck here)
#define SV_OUTPUTBUF_LENGTH (1024 - 16)
	char		sv_outputbuf[SV_OUTPUTBUF_LENGTH];
	static unsigned int lasttime = 0;
	char *cmd_aux;

	// TTimo - https://zerowing.idsoftware.com/bugzilla/show_bug.cgi?id=534
	time = Com_Milliseconds();
	if (time<(lasttime+500)) {
		return;
	}
	lasttime = time;

	if ( !strlen( sv_rconPassword->string ) ||
		strcmp (Cmd_Argv(1), sv_rconPassword->string) ) {
		valid = qfalse;
		Com_Printf ("Bad rcon from %s:\n%s\n", NET_AdrToString (from), Cmd_Argv(2) );
	} else {
		valid = qtrue;
		Com_Printf ("Rcon from %s:\n%s\n", NET_AdrToString (from), Cmd_Argv(2) );
	}

	// start redirecting all print outputs to the packet
	svs.redirectAddress = from;
	Com_BeginRedirect (sv_outputbuf, SV_OUTPUTBUF_LENGTH, SV_FlushRedirect);

	if ( !strlen( sv_rconPassword->string ) ) {
		Com_Printf ("No rconpassword set on the server.\n");
	} else if ( !valid ) {
		Com_Printf ("Bad rconpassword.\n");
	} else {
		remaining[0] = 0;
		
		// https://zerowing.idsoftware.com/bugzilla/show_bug.cgi?id=543
		// get the command directly, "rcon <pass> <command>" to avoid quoting issues
		// extract the command by walking
		// since the cmd formatting can fuckup (amount of spaces), using a dumb step by step parsing
		cmd_aux = Cmd_Cmd();
		cmd_aux+=4;
		while(cmd_aux[0]==' ')
			cmd_aux++;
		while(cmd_aux[0] && cmd_aux[0]!=' ') // password
			cmd_aux++;
		while(cmd_aux[0]==' ')
			cmd_aux++;
		
		Q_strcat( remaining, sizeof(remaining), cmd_aux);
		
		Cmd_ExecuteString (remaining);

	}

	Com_EndRedirect ();
}

/*
=================
SV_ConnectionlessPacket

A connectionless packet has four leading 0xff
characters to distinguish it from a game channel.
Clients that are in the game can still send
connectionless packets.
=================
*/
void SV_ConnectionlessPacket( netadr_t from, msg_t *msg ) {
	char	*s;
	char	*c;

	MSG_BeginReadingOOB( msg );
	MSG_ReadLong( msg );		// skip the -1 marker

	if (!Q_strncmp("connect", (char *) &msg->data[4], 7)) {
		Huff_Decompress(msg, 12);
	}

	s = MSG_ReadStringLine( msg );
	Cmd_TokenizeString( s );

	c = Cmd_Argv(0);
	Com_DPrintf ("SV packet %s : %s\n", NET_AdrToString(from), c);

	if (!Q_stricmp(c, "getstatus")) {
		SVC_Status( from  );
  } else if (!Q_stricmp(c, "getinfo")) {
		SVC_Info( from );
	} else if (!Q_stricmp(c, "getchallenge")) {
		SV_GetChallenge( from );
	} else if (!Q_stricmp(c, "connect")) {
		SV_DirectConnect( from );
	} else if (!Q_stricmp(c, "rcon")) {
		SVC_RemoteCommand( from, msg );
	} else if (!Q_stricmp(c, "disconnect")) {
		// if a client starts up a local server, we may see some spurious
		// server disconnect messages when their new server sees our final
		// sequenced messages to the old client
	} else {
		Com_DPrintf ("bad connectionless packet from %s:\n%s\n"
		, NET_AdrToString (from), s);
	}
}

//============================================================================

/*
=================
SV_ReadPackets
=================
*/
void SV_PacketEvent( netadr_t from, msg_t *msg ) {
	int			i;
	client_t	*cl;
	int			qport;

	// check for connectionless packet (0xffffffff) first
	if ( msg->cursize >= 4 && *(int *)msg->data == -1) {
		SV_ConnectionlessPacket( from, msg );
		return;
	}

	// read the qport out of the message so we can fix up
	// stupid address translating routers
	MSG_BeginReadingOOB( msg );
	MSG_ReadLong( msg );				// sequence number
	qport = MSG_ReadShort( msg ) & 0xffff;

	// find which client the message is from
	for (i=0, cl=svs.clients ; i < sv_maxclients->integer ; i++,cl++) {
		if (cl->state == CS_FREE) {
			continue;
		}
		if ( !NET_CompareBaseAdr( from, cl->netchan.remoteAddress ) ) {
			continue;
		}
		// it is possible to have multiple clients from a single IP
		// address, so they are differentiated by the qport variable
		if (cl->netchan.qport != qport) {
			continue;
		}

		// the IP port can't be used to differentiate them, because
		// some address translating routers periodically change UDP
		// port assignments
		if (cl->netchan.remoteAddress.port != from.port) {
			Com_Printf( "SV_PacketEvent: fixing up a translated port\n" );
			cl->netchan.remoteAddress.port = from.port;
		}

		// make sure it is a valid, in sequence packet
		if (SV_Netchan_Process(cl, msg)) {
			// zombie clients still need to do the Netchan_Process
			// to make sure they don't need to retransmit the final
			// reliable message, but they don't do any other processing
			if (cl->state != CS_ZOMBIE) {
				cl->lastPacketTime = svs.time;	// don't timeout
				SV_ExecuteClientMessage( cl, msg );
			}
		}
		return;
	}
	
	// if we received a sequenced packet from an address we don't recognize,
	// send an out of band disconnect packet to it
	NET_OutOfBandPrint( NS_SERVER, from, "disconnect" );
}


/*
===================
SV_CalcPings

Updates the cl->ping variables
===================
*/
void SV_CalcPings( void ) {
	int			i, j;
	client_t	*cl;
	int			total, count;
	int			delta;
	playerState_t	*ps;

	for (i=0 ; i < sv_maxclients->integer ; i++) {
		cl = &svs.clients[i];
		if ( cl->state != CS_ACTIVE ) {
			cl->ping = 999;
			continue;
		}
		if ( !cl->gentity ) {
			cl->ping = 999;
			continue;
		}
		if ( cl->gentity->r.svFlags & SVF_BOT ) {
			cl->ping = 0;
			continue;
		}

		total = 0;
		count = 0;
		for ( j = 0 ; j < PACKET_BACKUP ; j++ ) {
			if ( cl->frames[j].messageAcked <= 0 ) {
				continue;
			}
			delta = cl->frames[j].messageAcked - cl->frames[j].messageSent;
			count++;
			total += delta;
		}
		if (!count) {
			cl->ping = 999;
		} else {
			cl->ping = total/count;
			if ( cl->ping > 999 ) {
				cl->ping = 999;
			}
		}

		// let the game dll know about the ping
		ps = SV_GameClientNum( i );
		ps->ping = cl->ping;
	}
}

/*
==================
SV_CheckTimeouts

If a packet has not been received from a client for timeout->integer 
seconds, drop the conneciton.  Server time is used instead of
realtime to avoid dropping the local client while debugging.

When a client is normally dropped, the client_t goes into a zombie state
for a few seconds to make sure any final reliable message gets resent
if necessary
==================
*/
void SV_CheckTimeouts( void ) {
	int		i;
	client_t	*cl;
	int			droppoint;
	int			zombiepoint;

	droppoint = svs.time - 1000 * sv_timeout->integer;
	zombiepoint = svs.time - 1000 * sv_zombietime->integer;

	for (i=0,cl=svs.clients ; i < sv_maxclients->integer ; i++,cl++) {
		// message times may be wrong across a changelevel
		if (cl->lastPacketTime > svs.time) {
			cl->lastPacketTime = svs.time;
		}

		if (cl->state == CS_ZOMBIE
		&& cl->lastPacketTime < zombiepoint) {
			// using the client id cause the cl->name is empty at this point
			Com_DPrintf( "Going from CS_ZOMBIE to CS_FREE for client %d\n", i );
			cl->state = CS_FREE;	// can now be reused
			continue;
		}
		if ( cl->state >= CS_CONNECTED && cl->lastPacketTime < droppoint) {
			// wait several frames so a debugger session doesn't
			// cause a timeout
			if ( ++cl->timeoutCount > 5 ) {
				SV_DropClient (cl, "timed out"); 
				cl->state = CS_FREE;	// don't bother with zombie state
			}
		} else {
			cl->timeoutCount = 0;
		}
	}
}


/*
==================
SV_CheckPaused
==================
*/
qboolean SV_CheckPaused( void ) {
	int		count;
	client_t	*cl;
	int		i;

	if ( !cl_paused->integer ) {
		return qfalse;
	}

	// only pause if there is just a single client connected
	count = 0;
	for (i=0,cl=svs.clients ; i < sv_maxclients->integer ; i++,cl++) {
		if ( cl->state >= CS_CONNECTED && cl->netchan.remoteAddress.type != NA_BOT ) {
			count++;
		}
	}

	if ( count > 1 ) {
		// don't pause
		if (sv_paused->integer)
			Cvar_Set("sv_paused", "0");
		return qfalse;
	}

	if (!sv_paused->integer)
		Cvar_Set("sv_paused", "1");
	return qtrue;
}

/*
==================
SV_Frame

Player movement occurs as a result of packet events, which
happen before SV_Frame is called
==================
*/
void SV_Frame( int msec ) {
	int		frameMsec;
	int		startTime;

	// the menu kills the server with this cvar
	if ( sv_killserver->integer ) {
		SV_Shutdown ("Server was killed.\n");
		Cvar_Set( "sv_killserver", "0" );
		return;
	}

	if ( !com_sv_running->integer ) {
		return;
	}

	// allow pause if only the local client is connected
	if ( SV_CheckPaused() ) {
		return;
	}

	// if it isn't time for the next frame, do nothing
	if ( sv_fps->integer < 1 ) {
		Cvar_Set( "sv_fps", "10" );
	}
	frameMsec = 1000 / sv_fps->integer ;

	sv.timeResidual += msec;

	if (!com_dedicated->integer) SV_BotFrame (sv.time + sv.timeResidual);

	if ( com_dedicated->integer && sv.timeResidual < frameMsec ) {
		// NET_Sleep will give the OS time slices until either get a packet
		// or time enough for a server frame has gone by
		NET_Sleep(frameMsec - sv.timeResidual);
		return;
	}

	// if time is about to hit the 32nd bit, kick all clients
	// and clear sv.time, rather
	// than checking for negative time wraparound everywhere.
	// 2giga-milliseconds = 23 days, so it won't be too often
	if ( svs.time > 0x70000000 ) {
		SV_Shutdown( "Restarting server due to time wrapping" );
		Cbuf_AddText( va( "map %s\n", Cvar_VariableString( "mapname" ) ) );
		return;
	}
	// this can happen considerably earlier when lots of clients play and the map doesn't change
	if ( svs.nextSnapshotEntities >= 0x7FFFFFFE - svs.numSnapshotEntities ) {
		SV_Shutdown( "Restarting server due to numSnapshotEntities wrapping" );
		Cbuf_AddText( va( "map %s\n", Cvar_VariableString( "mapname" ) ) );
		return;
	}

	if( sv.restartTime && svs.time >= sv.restartTime ) {
		sv.restartTime = 0;
		Cbuf_AddText( "map_restart 0\n" );
		return;
	}

	// update infostrings if anything has been changed
	if ( cvar_modifiedFlags & CVAR_SERVERINFO ) {
		SV_SetConfigstring( CS_SERVERINFO, Cvar_InfoString( CVAR_SERVERINFO ) );
		cvar_modifiedFlags &= ~CVAR_SERVERINFO;
	}
	if ( cvar_modifiedFlags & CVAR_SYSTEMINFO ) {
		SV_SetConfigstring( CS_SYSTEMINFO, Cvar_InfoString_Big( CVAR_SYSTEMINFO ) );
		cvar_modifiedFlags &= ~CVAR_SYSTEMINFO;
	}

	if ( com_speeds->integer ) {
		startTime = Sys_Milliseconds ();
	} else {
		startTime = 0;	// quite a compiler warning
	}

	// update ping based on the all received frames
	SV_CalcPings();

	if (com_dedicated->integer) SV_BotFrame (sv.time);

	// run the game simulation in chunks
	while ( sv.timeResidual >= frameMsec ) {
		sv.timeResidual -= frameMsec;
		svs.time += frameMsec;
		sv.time += frameMsec;

		// let everything in the world think and move
		VM_Call (gvm, GAME_RUN_FRAME, sv.time);
	}

	if ( com_speeds->integer ) {
		time_game = Sys_Milliseconds () - startTime;
	}

	// check timeouts
	SV_CheckTimeouts();

	// send messages back to the clients
	SV_SendClientMessages();

	// send a heartbeat to the master if needed
	SV_MasterHeartbeat();
}

//============================================================================