sv_main.c

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/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.

This file is part of Quake III Arena source code.

Quake III Arena source code 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.

Quake III Arena source code 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 Foobar; 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_gametype;
cvar_t  *sv_pure;
cvar_t  *sv_floodProtect;
cvar_t  *sv_lanForceRate; // dedicated 1 (LAN) server forces local client rates to 99999 (bug #491)
cvar_t  *sv_strictAuth;

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

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);

    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  "QuakeArena-1"
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
}


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

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];

    // ignore if we are in single player
    if ( Cvar_VariableValue( "g_gametype" ) == GT_SINGLE_PLAYER ) {
        return;
    }

    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];

    // ignore if we are in single player
    if ( Cvar_VariableValue( "g_gametype" ) == GT_SINGLE_PLAYER || Cvar_VariableValue("ui_singlePlayerActive")) {
        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, "gametype", va("%i", sv_gametype->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", &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, "ipAuthorize")) {
        SV_AuthorizeIpPacket( 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( svs.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( "vstr nextmap\n" );
        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( "vstr nextmap\n" );
        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( svs.time );

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

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

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

---