d_net.cpp

// Emacs style mode select	 -*- C++ -*- 
//-----------------------------------------------------------------------------
//
// $Id:$
//
// Copyright (C) 1993-1996 by id Software, Inc.
// Copyright 1999-2016 Randy Heit
// Copyright 2002-2020 Christoph Oelckers
//
// This program 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 3 of the License, or
// (at your option) any later version.
//
// This program 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 this program.  If not, see http://www.gnu.org/licenses/
//
//
//
// Alternatively the following applies:
//
// This source is available for distribution and/or modification
// only under the terms of the DOOM Source Code License as
// published by id Software. All rights reserved.
//
// The source is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// FITNESS FOR A PARTICULAR PURPOSE. See the DOOM Source Code License
// for more details.
//
// $Log:$
//
// DESCRIPTION:
//		DOOM Network game communication and protocol,
//		all OS independent parts.
//
//-----------------------------------------------------------------------------

#include <stddef.h>
#define __STDC_FORMAT_MACROS
#include <inttypes.h>

#include "version.h"
#include "razemenu.h"
#include "i_video.h"
#include "c_console.h"
#include "d_net.h"
#include "d_protocol.h"
#include "cmdlib.h"
#include "c_dispatch.h"
#include "gameconfigfile.h"
#include "st_start.h"
#include "d_event.h"
#include "m_argv.h"
#include "hardware.h"
#include "i_time.h"
#include "i_system.h"
#include "vm.h"
#include "gstrings.h"
#include "s_music.h"
#include "printf.h"
#include "i_time.h"
#include "d_ticcmd.h"
#include "m_random.h"
#include "cheats.h"

extern bool pauseext;
extern int gametic;

// Placeholders to make it compile.
FILE* debugfile;
bool demoplayback;
int Net_Arbitrator;
bool playeringame[MAXPLAYERS] = { true }; // as long as network isn't working - true for the first player, false for all others.
bool singletics;
char* startmap;
bool autostart;
bool usergame;
void D_ReadUserInfoStrings(int, uint8_t**, bool) {}
void D_WriteUserInfoStrings(int, uint8_t**, bool) {}
FString GetPlayerName(int num);

//#define SIMULATEERRORS		(RAND_MAX/3)
#define SIMULATEERRORS			0

extern uint8_t		*demo_p;		// [RH] Special "ticcmds" get recorded in demos
extern FString	savedescription;
extern FString	savegamefile;

short consistency[MAXPLAYERS][BACKUPTICS];

#define netbuffer (doomcom.data)

enum { NET_PeerToPeer, NET_PacketServer };
uint8_t NetMode = NET_PeerToPeer;



//
// NETWORKING
//
// gametic is the tic about to (or currently being) run
// maketic is the tick that hasn't had control made for it yet
// nettics[] has the maketics for all players 
//
// a gametic cannot be run until nettics[] > gametic for all players
//
#define RESENDCOUNT 	10
#define PL_DRONE		0x80	// bit flag in doomdata->player

ticcmd_t		localcmds[LOCALCMDTICS];

FDynamicBuffer	NetSpecs[MAXPLAYERS][BACKUPTICS];
ticcmd_t		netcmds[MAXPLAYERS][BACKUPTICS];
int 			nettics[MAXNETNODES];
bool 			nodeingame[MAXNETNODES];				// set false as nodes leave game
bool			nodejustleft[MAXNETNODES];				// set when a node just left
bool	 		remoteresend[MAXNETNODES];				// set when local needs tics
int 			resendto[MAXNETNODES];					// set when remote needs tics
int 			resendcount[MAXNETNODES];	

uint64_t		lastrecvtime[MAXPLAYERS];				// [RH] Used for pings
uint64_t		currrecvtime[MAXPLAYERS];
uint64_t		lastglobalrecvtime;						// Identify the last time a packet was received.
bool			hadlate;
int				netdelay[MAXNETNODES][BACKUPTICS];		// Used for storing network delay times.
int				lastaverage;

int 			nodeforplayer[MAXPLAYERS];
int				playerfornode[MAXNETNODES];

int 			maketic;
int 			skiptics;
int 			ticdup;

void D_ProcessEvents (void); 
void G_BuildTiccmd (ticcmd_t *cmd); 
void D_DoAdvanceDemo (void);

static void SendSetup (uint32_t playersdetected[MAXNETNODES], uint8_t gotsetup[MAXNETNODES], int len);
static void RunScript(uint8_t **stream, AActor *pawn, int snum, int argn, int always);

int		reboundpacket;
uint8_t	reboundstore[MAX_MSGLEN];

int 	frameon;
int 	frameskip[4];
int 	oldnettics;
int		mastertics;

static int 	entertic;
static int	oldentertics;

extern	bool	 advancedemo;

CVAR(Bool, net_ticbalance, false, CVAR_SERVERINFO | CVAR_NOSAVE)
CUSTOM_CVAR(Int, net_extratic, 0, CVAR_SERVERINFO | CVAR_NOSAVE)
{
	if (self < 0)
	{
		self = 0;
	}
	else if (self > 2)
	{
		self = 2;
	}
}

#ifdef _DEBUG
CVAR(Int, net_fakelatency, 0, 0);

struct PacketStore
{
	int timer;
	doomcom_t message;
};

static TArray<PacketStore> InBuffer;
static TArray<PacketStore> OutBuffer;
#endif

// [RH] Special "ticcmds" get stored in here
static struct TicSpecial
{
	uint8_t *streams[BACKUPTICS];
	size_t used[BACKUPTICS];
	uint8_t *streamptr;
	size_t streamoffs;
	size_t specialsize;
	int	  lastmaketic;
	bool  okay;

	TicSpecial ()
	{
		int i;

		lastmaketic = -1;
		specialsize = 256;

		for (i = 0; i < BACKUPTICS; i++)
			streams[i] = NULL;

		for (i = 0; i < BACKUPTICS; i++)
		{
			streams[i] = (uint8_t *)M_Malloc (256);
			used[i] = 0;
		}
		okay = true;
	}

	~TicSpecial ()
	{
		int i;

		for (i = 0; i < BACKUPTICS; i++)
		{
			if (streams[i])
			{
				M_Free (streams[i]);
				streams[i] = NULL;
				used[i] = 0;
			}
		}
		okay = false;
	}

	// Make more room for special commands.
	void GetMoreSpace (size_t needed)
	{
		int i;

		specialsize = std::max(specialsize * 2, needed + 30);

		DPrintf (DMSG_NOTIFY, "Expanding special size to %zu\n", specialsize);

		for (i = 0; i < BACKUPTICS; i++)
			streams[i] = (uint8_t *)M_Realloc (streams[i], specialsize);

		streamptr = streams[(maketic/ticdup)%BACKUPTICS] + streamoffs;
	}

	void CheckSpace (size_t needed)
	{
		if (streamoffs + needed >= specialsize)
			GetMoreSpace (streamoffs + needed);

		streamoffs += needed;
	}

	void NewMakeTic ()
	{
		int mt = maketic / ticdup;
		if (lastmaketic != -1)
		{
			if (lastmaketic == mt)
				return;
			used[lastmaketic%BACKUPTICS] = streamoffs;
		}

		lastmaketic = mt;
		streamptr = streams[mt%BACKUPTICS];
		streamoffs = 0;
	}

	TicSpecial &operator << (uint8_t it)
	{
		if (streamptr)
		{
			CheckSpace (1);
			WriteByte (it, &streamptr);
		}
		return *this;
	}

	TicSpecial &operator << (short it)
	{
		if (streamptr)
		{
			CheckSpace (2);
			WriteWord (it, &streamptr);
		}
		return *this;
	}

	TicSpecial &operator << (int it)
	{
		if (streamptr)
		{
			CheckSpace (4);
			WriteLong (it, &streamptr);
		}
		return *this;
	}

	TicSpecial &operator << (float it)
	{
		if (streamptr)
		{
			CheckSpace (4);
			WriteFloat (it, &streamptr);
		}
		return *this;
	}

	TicSpecial &operator << (const char *it)
	{
		if (streamptr)
		{
			CheckSpace (strlen (it) + 1);
			WriteString (it, &streamptr);
		}
		return *this;
	}

} specials;

void Net_ClearBuffers ()
{
	int i, j;

	memset (localcmds, 0, sizeof(localcmds));
	memset (netcmds, 0, sizeof(netcmds));
	memset (nettics, 0, sizeof(nettics));
	memset (nodeingame, 0, sizeof(nodeingame));
	memset (nodeforplayer, 0, sizeof(nodeforplayer));
	memset (playerfornode, 0, sizeof(playerfornode));
	memset (remoteresend, 0, sizeof(remoteresend));
	memset (resendto, 0, sizeof(resendto));
	memset (resendcount, 0, sizeof(resendcount));
	memset (lastrecvtime, 0, sizeof(lastrecvtime));
	memset (currrecvtime, 0, sizeof(currrecvtime));
	memset (consistency, 0, sizeof(consistency));
	nodeingame[0] = true;

	for (i = 0; i < MAXPLAYERS; i++)
	{
		for (j = 0; j < BACKUPTICS; j++)
		{
			NetSpecs[i][j].SetData (NULL, 0);
		}
	}

	oldentertics = entertic;
	gametic = 0;
	maketic = 0;

	lastglobalrecvtime = 0;
}

//
// [RH] Rewritten to properly calculate the packet size
//		with our variable length commands.
//
int NetbufferSize ()
{
	if (netbuffer[0] & (NCMD_EXIT | NCMD_SETUP))
	{
		return doomcom.datalength;
	}

	int k = 2, count, numtics;

	if (netbuffer[0] & NCMD_RETRANSMIT)
		k++;

	if (NetMode == NET_PacketServer && doomcom.remotenode == nodeforplayer[Net_Arbitrator])
		k++;

	numtics = netbuffer[0] & NCMD_XTICS;
	if (numtics == 3)
	{
		numtics += netbuffer[k++];
	}

	if (netbuffer[0] & NCMD_QUITTERS)
	{
		k += netbuffer[k] + 1;
	}

	// Network delay byte
	k++;

	if (netbuffer[0] & NCMD_MULTI)
	{
		count = netbuffer[k];
		k += count;
	}
	else
	{
		count = 1;
	}

	// Need at least 3 bytes per tic per player
	if (doomcom.datalength < k + 3 * count * numtics)
	{
		return k + 3 * count * numtics;
	}

	uint8_t *skipper = &netbuffer[k];
	if ((netbuffer[0] & NCMD_EXIT) == 0)
	{
		while (count-- > 0)
		{
			SkipTicCmd (&skipper, numtics);
		}
	}
	return int(skipper - netbuffer);
}

//
//
//
int ExpandTics (int low)
{
	int delta;
	int mt = maketic / ticdup;

	delta = low - (mt&0xff);
		
	if (delta >= -64 && delta <= 64)
		return (mt&~0xff) + low;
	if (delta > 64)
		return (mt&~0xff) - 256 + low;
	if (delta < -64)
		return (mt&~0xff) + 256 + low;
				
	I_Error ("ExpandTics: strange value %i at maketic %i", low, maketic);
	return 0;
}



//
// HSendPacket
//
void HSendPacket (int node, int len)
{
	if (debugfile && node != 0)
	{
		int i, k, realretrans;

		if (netbuffer[0] & NCMD_SETUP)
		{
			fprintf (debugfile,"%i/%i send %i = SETUP [%3i]", gametic, maketic, node, len);
			for (i = 0; i < len; i++)
				fprintf (debugfile," %2x", ((uint8_t *)netbuffer)[i]);
		}
		else if (netbuffer[0] & NCMD_EXIT)
		{
			fprintf (debugfile,"%i/%i send %i = EXIT [%3i]", gametic, maketic, node, len);
			for (i = 0; i < len; i++)
				fprintf (debugfile," %2x", ((uint8_t *)netbuffer)[i]);
		}
		else
		{
			k = 2;

			if (NetMode == NET_PacketServer && myconnectindex == Net_Arbitrator &&
				node != 0)
			{
				k++;
			}

			if (netbuffer[0] & NCMD_RETRANSMIT)
				realretrans = ExpandTics (netbuffer[k++]);
			else
				realretrans = -1;

			int numtics = netbuffer[0] & 3;
			if (numtics == 3)
				numtics += netbuffer[k++];

			fprintf (debugfile,"%i/%i send %i = (%i + %i, R %i) [%3i]",
					gametic, maketic,
					node,
					ExpandTics(netbuffer[1]),
					numtics, realretrans, len);
			
			for (i = 0; i < len; i++)
				fprintf (debugfile, "%c%2x", i==k?'|':' ', ((uint8_t *)netbuffer)[i]);
		}
		fprintf (debugfile, " [[ ");
		for (i = 0; i < doomcom.numnodes; ++i)
		{
			if (nodeingame[i])
			{
				fprintf (debugfile, "%d ", nettics[i]);
			}
			else
			{
				fprintf (debugfile, "--- ");
			}
		}
		fprintf (debugfile, "]]\n");
	}

	if (node == 0)
	{
		memcpy (reboundstore, netbuffer, len);
		reboundpacket = len;
		return;
	}

	if (demoplayback)
		return;

	if (!netgame)
		I_Error ("Tried to transmit to another node");

#if SIMULATEERRORS
	if (rand() < SIMULATEERRORS)
	{
		if (debugfile)
			fprintf (debugfile, "Drop!\n");
		return;
	}
#endif

	doomcom.command = CMD_SEND;
	doomcom.remotenode = node;
	doomcom.datalength = len;

#ifdef _DEBUG
	if (net_fakelatency / 2 > 0)
	{
		PacketStore store;
		store.message = doomcom;
		store.timer = I_GetTime() + ((net_fakelatency / 2) / (1000 / GameTicRate));
		OutBuffer.Push(store);
	}
	else
		I_NetCmd();

	for (unsigned int i = 0; i < OutBuffer.Size(); i++)
	{
		if (OutBuffer[i].timer <= I_GetTime())
		{
			doomcom = OutBuffer[i].message;
			I_NetCmd();
			OutBuffer.Delete(i);
			i = -1;
		}
	}
#else
	I_NetCmd();
#endif
}

//
// HGetPacket
// Returns false if no packet is waiting
//
bool HGetPacket (void)
{
	if (reboundpacket)
	{
		memcpy (netbuffer, reboundstore, reboundpacket);
		doomcom.remotenode = 0;
		reboundpacket = 0;
		return true;
	}

	if (!netgame)
		return false;

	if (demoplayback)
		return false;

	doomcom.command = CMD_GET;
	I_NetCmd ();

#ifdef _DEBUG
	if (net_fakelatency / 2 > 0 && doomcom.remotenode != -1)
	{
		PacketStore store;
		store.message = doomcom;
		store.timer = I_GetTime() + ((net_fakelatency / 2) / (1000 / GameTicRate));
		InBuffer.Push(store);
		doomcom.remotenode = -1;
	}
	
	if (doomcom.remotenode == -1)
	{
		bool gotmessage = false;
		for (unsigned int i = 0; i < InBuffer.Size(); i++)
		{
			if (InBuffer[i].timer <= I_GetTime())
			{
				doomcom = InBuffer[i].message;
				InBuffer.Delete(i);
				gotmessage = true;
				break;
			}
		}
		if (!gotmessage)
			return false;
	}
#else
	if (doomcom.remotenode == -1)
	{
		return false;
	}
#endif
		
	if (debugfile)
	{
		int i, k, realretrans;

		if (netbuffer[0] & NCMD_SETUP)
		{
			fprintf (debugfile,"%i/%i  get %i = SETUP [%3i]", gametic, maketic, doomcom.remotenode, doomcom.datalength);
			for (i = 0; i < doomcom.datalength; i++)
				fprintf (debugfile, " %2x", ((uint8_t *)netbuffer)[i]);
			fprintf (debugfile, "\n");
		}
		else if (netbuffer[0] & NCMD_EXIT)
		{
			fprintf (debugfile,"%i/%i  get %i = EXIT [%3i]", gametic, maketic, doomcom.remotenode, doomcom.datalength);
			for (i = 0; i < doomcom.datalength; i++)
				fprintf (debugfile, " %2x", ((uint8_t *)netbuffer)[i]);
			fprintf (debugfile, "\n");
		}
		else		{
			k = 2;

			if (NetMode == NET_PacketServer &&
				doomcom.remotenode == nodeforplayer[Net_Arbitrator])
			{
				k++;
			}

			if (netbuffer[0] & NCMD_RETRANSMIT)
				realretrans = ExpandTics (netbuffer[k++]);
			else
				realretrans = -1;

			int numtics = netbuffer[0] & 3;
			if (numtics == 3)
				numtics += netbuffer[k++];

			fprintf (debugfile,"%i/%i  get %i = (%i + %i, R %i) [%3i]",
					gametic, maketic,
					doomcom.remotenode,
					ExpandTics(netbuffer[1]),
					numtics, realretrans, doomcom.datalength);
			
			for (i = 0; i < doomcom.datalength; i++)
				fprintf (debugfile, "%c%2x", i==k?'|':' ', ((uint8_t *)netbuffer)[i]);
			if (numtics)
				fprintf (debugfile, " <<%4x>>\n",
					consistency[playerfornode[doomcom.remotenode]][nettics[doomcom.remotenode]%BACKUPTICS] & 0xFFFF);
			else
				fprintf (debugfile, "\n");
		}
	}

	if (doomcom.datalength != NetbufferSize ())
	{
		Printf("Bad packet length %i (calculated %i)\n",
			doomcom.datalength, NetbufferSize());

		if (debugfile)
			fprintf (debugfile,"---bad packet length %i (calculated %i)\n",
				doomcom.datalength, NetbufferSize());
		return false;
	}

	return true;		
}

void PlayerIsGone (int netnode, int netconsole)
{
	int i;

	if (nodeingame[netnode])
	{
		for (i = netnode + 1; i < doomcom.numnodes; ++i)
		{
			if (nodeingame[i])
				break;
		}
		if (i == doomcom.numnodes)
		{
			doomcom.numnodes = netnode;
		}

#if 0
		if (playeringame[netconsole])
		{
			players[netconsole].playerstate = PST_GONE;
		}
#endif
		nodeingame[netnode] = false;
		nodejustleft[netnode] = false;
	}
	else if (nodejustleft[netnode]) // Packet Server
	{
		if (netnode + 1 == doomcom.numnodes)
		{
			doomcom.numnodes = netnode;
		}
#if 0
		if (playeringame[netconsole])
		{
			players[netconsole].playerstate = PST_GONE;
		}
#endif
		nodejustleft[netnode] = false;
	}
	else return;

	if (netconsole == Net_Arbitrator)
	{
		// Pick a new network arbitrator
		for (int i = 0; i < MAXPLAYERS; i++)
		{
#if 0
			if (i != netconsole && playeringame[i] && players[i].Bot == NULL)
			{
				Net_Arbitrator = i;
				players[i].settings_controller = true;
				Printf("%s is the new arbitrator\n", players[i].userinfo.GetName());
				break;
			}
#endif
		}
	}

	if (debugfile && NetMode == NET_PacketServer)
	{
		if (Net_Arbitrator == myconnectindex)
		{
			fprintf(debugfile, "I am the new master!\n");
		}
		else
		{
			fprintf(debugfile, "Node %d is the new master!\n", nodeforplayer[Net_Arbitrator]);
		}
	}

#if 0
	if (demorecording)
	{
		G_CheckDemoStatus ();

		//WriteByte (DEM_DROPPLAYER, &demo_p);
		//WriteByte ((uint8_t)netconsole, &demo_p);
	}
#endif
}

//
// GetPackets
//

void GetPackets (void)
{
	int netconsole;
	int netnode;
	int realend;
	int realstart;
	int numtics;
	int retransmitfrom;
	int k;
	uint8_t playerbytes[MAXNETNODES];
	int numplayers;
								 
	while ( HGetPacket() )
	{
		if (netbuffer[0] & NCMD_SETUP)
		{
			if (myconnectindex == Net_Arbitrator)
			{
				// This player apparantly doesn't realise the game has started
				netbuffer[0] = NCMD_SETUP+3;
				HSendPacket (doomcom.remotenode, 1);
			}
			continue;			// extra setup packet
		}
						
		netnode = doomcom.remotenode;
		netconsole = playerfornode[netnode] & ~PL_DRONE;

		// [RH] Get "ping" times - totally useless, since it's bound to the frequency
		// packets go out at.
		lastrecvtime[netconsole] = currrecvtime[netconsole];
		currrecvtime[netconsole] = I_msTime ();

		// check for exiting the game
		if (netbuffer[0] & NCMD_EXIT)
		{
			if (!nodeingame[netnode])
				continue;

			if (NetMode != NET_PacketServer || netconsole == Net_Arbitrator)
			{
				PlayerIsGone (netnode, netconsole);
				if (NetMode == NET_PacketServer)
				{
					uint8_t *foo = &netbuffer[2];
					for (int i = 0; i < MAXPLAYERS; ++i)
					{
						if (playeringame[i])
						{
							int resend = ReadLong (&foo);
							if (i != myconnectindex)
							{
								resendto[nodeforplayer[i]] = resend;
							}
						}
					}
				}
			}
			else
			{
				nodeingame[netnode] = false;
				nodejustleft[netnode] = true;
			}
			continue;
		}

		k = 2;

		if (NetMode == NET_PacketServer &&
			netconsole == Net_Arbitrator &&
			netconsole != myconnectindex)
		{
			mastertics = ExpandTics (netbuffer[k++]);
		}

		if (netbuffer[0] & NCMD_RETRANSMIT)
		{
			retransmitfrom = netbuffer[k++];
		}
		else
		{
			retransmitfrom = 0;
		}

		numtics = (netbuffer[0] & NCMD_XTICS);
		if (numtics == 3)
		{
			numtics += netbuffer[k++];
		}

		if (netbuffer[0] & NCMD_QUITTERS)
		{
			numplayers = netbuffer[k++];
			for (int i = 0; i < numplayers; ++i)
			{
				PlayerIsGone (nodeforplayer[netbuffer[k]], netbuffer[k]);
				k++;
			}
		}

		// Pull current network delay from node
		netdelay[netnode][(nettics[netnode]+1) % BACKUPTICS] = netbuffer[k++];

		playerbytes[0] = netconsole;
		if (netbuffer[0] & NCMD_MULTI)
		{
			numplayers = netbuffer[k++];
			memcpy (playerbytes+1, &netbuffer[k], numplayers - 1);
			k += numplayers - 1;
		}
		else
		{
			numplayers = 1;
		}

		// to save bytes, only the low byte of tic numbers are sent
		// Figure out what the rest of the bytes are
		realstart = ExpandTics (netbuffer[1]);
		realend = (realstart + numtics);
		
		nodeforplayer[netconsole] = netnode;
		
		// check for retransmit request
		if (resendcount[netnode] <= 0 && (netbuffer[0] & NCMD_RETRANSMIT))
		{
			resendto[netnode] = ExpandTics (retransmitfrom);
			if (debugfile)
				fprintf (debugfile,"retransmit from %i\n", resendto[netnode]);
			resendcount[netnode] = RESENDCOUNT;
		}
		else
		{
			resendcount[netnode]--;
		}
		
		// check for out of order / duplicated packet			
		if (realend == nettics[netnode])
			continue;
						
		if (realend < nettics[netnode])
		{
			if (debugfile)
				fprintf (debugfile, "out of order packet (%i + %i)\n" ,
						 realstart, numtics);
			continue;
		}
		
		// check for a missed packet
		if (realstart > nettics[netnode])
		{
			// stop processing until the other system resends the missed tics
			if (debugfile)
				fprintf (debugfile, "missed tics from %i (%i to %i)\n",
						 netnode, nettics[netnode], realstart);
			remoteresend[netnode] = true;
			continue;
		}

		// update command store from the packet
		{
			uint8_t *start;
			int i, tics;
			remoteresend[netnode] = false;

			start = &netbuffer[k];

			for (i = 0; i < numplayers; ++i)
			{
				int node = nodeforplayer[playerbytes[i]];

				SkipTicCmd (&start, nettics[node] - realstart);
				for (tics = nettics[node]; tics < realend; tics++)
					ReadTicCmd (&start, playerbytes[i], tics);

				nettics[nodeforplayer[playerbytes[i]]] = realend;
			}
		}
	}
}

//
// NetUpdate
// Builds ticcmds for console player,
// sends out a packet
//
int gametime;

void NetUpdate (void)
{
	int		lowtic;
	int 	nowtime;
	int 	newtics;
	int 	i,j;
	int 	realstart;
	uint8_t	*cmddata;
	bool	resendOnly;

	GC::CheckGC();

	if (ticdup == 0)
	{
		return;
	}

	// check time
	nowtime = I_GetTime ();
	newtics = nowtime - gametime;
	gametime = nowtime;

	if (newtics <= 0)	// nothing new to update
	{
		GetPackets ();
		return;
	}

	if (skiptics <= newtics)
	{
		newtics -= skiptics;
		skiptics = 0;
	}
	else
	{
		skiptics -= newtics;
		newtics = 0;
	}

	// build new ticcmds for console player
	for (i = 0; i < newtics; i++)
	{
		I_StartTic ();
		D_ProcessEvents ();
		if (pauseext || (maketic - gametic) / ticdup >= BACKUPTICS/2-1)
			break;			// can't hold any more
		
		//Printf ("mk:%i ",maketic);
		G_BuildTiccmd (&localcmds[maketic % LOCALCMDTICS]);
		maketic++;

		if (ticdup == 1 || maketic == 0)
		{
			Net_NewMakeTic ();
		}
		else
		{
			// Once ticdup tics have been collected, average their movements
			// and combine their buttons, since they will all be sent as a
			// single tic that gets duplicated ticdup times. Even with ticdup,
			// tics are still collected at the normal rate so that, with the
			// help of prediction, the game seems as responsive as normal.
			if (maketic % ticdup != 0)
			{
				int mod = maketic - maketic % ticdup;
				int j;

				// Update the buttons for all tics in this ticdup set as soon as
				// possible so that the prediction shows jumping as correctly as
				// possible. (If you press +jump in the middle of a ticdup set,
				// the jump will actually begin at the beginning of the set, not
				// in the middle.)
				for (j = maketic-2; j >= mod; --j)
				{
					localcmds[j % LOCALCMDTICS].ucmd.actions |=
						localcmds[(j + 1) % LOCALCMDTICS].ucmd.actions;
					localcmds[j % LOCALCMDTICS].ucmd.setNewWeapon(localcmds[(j + 1) % LOCALCMDTICS].ucmd.getNewWeapon());
				}
			}
			else
			{
				// Average the ticcmds between these tics to get the
				// movement that is actually sent across the network. We
				// need to update them in all the localcmds slots that
				// are dupped so that prediction works properly.
				int mod = maketic - ticdup;
				int modp, j;

				int svel = 0;
				int fvel = 0;
				float avel = 0;
				float horz = 0;

				for (j = 0; j < ticdup; ++j)
				{
					modp = (mod + j) % LOCALCMDTICS;
					svel += localcmds[modp].ucmd.svel;
					fvel += localcmds[modp].ucmd.fvel;
					avel += localcmds[modp].ucmd.avel;
					horz += localcmds[modp].ucmd.horz;
				}

				svel /= ticdup;
				fvel /= ticdup;
				avel /= ticdup;
				horz /= ticdup;

				for (j = 0; j < ticdup; ++j)
				{
					modp = (mod + j) % LOCALCMDTICS;
					localcmds[modp].ucmd.svel = svel;
					localcmds[modp].ucmd.fvel = fvel;
					localcmds[modp].ucmd.avel = avel;
					localcmds[modp].ucmd.horz = horz;
				}

				Net_NewMakeTic ();
			}
		}
	}

	if (singletics)
		return; 		// singletic update is synchronous

	if (demoplayback)
	{
		resendto[0] = nettics[0] = (maketic / ticdup);
		return;			// Don't touch netcmd data while playing a demo, as it'll already exist.
	}

	// If maketic didn't cross a ticdup boundary, only send packets
	// to players waiting for resends.
	resendOnly = (maketic / ticdup) == (maketic - i) / ticdup;

	// send the packet to the other nodes
	int count = 1;
	int quitcount = 0;

	if (myconnectindex == Net_Arbitrator)
	{
		if (NetMode == NET_PacketServer)
		{
			for (j = 0; j < MAXPLAYERS; j++)
			{
				if (playeringame[j])
				{
					count++;
				}
			}

			// The loop above added the local player to the count a second time,
			// and it also added the player being sent the packet to the count.
			count -= 2;

			for (j = 0; j < doomcom.numnodes; ++j)
			{
				if (nodejustleft[j])
				{
					if (count == 0)
					{
						PlayerIsGone (j, playerfornode[j]);
					}
					else
					{
						quitcount++;
					}
				}
			}

			if (count == 0)
			{
				count = 1;
			}
		}
	}

	for (i = 0; i < doomcom.numnodes; i++)
	{
		uint8_t playerbytes[MAXPLAYERS];

		if (!nodeingame[i])
		{
			continue;
		}
		if (NetMode == NET_PacketServer &&
			myconnectindex != Net_Arbitrator &&
			i != nodeforplayer[Net_Arbitrator] &&
			i != 0)
		{
			continue;
		}
		if (resendOnly && resendcount[i] <= 0 && !remoteresend[i] && nettics[i])
		{
			continue;
		}

		int numtics;
		int k;

		lowtic = maketic / ticdup;

		netbuffer[0] = 0;
		netbuffer[1] = realstart = resendto[i];
		k = 2;

		if (NetMode == NET_PacketServer &&
			myconnectindex == Net_Arbitrator &&
			i != 0)
		{
			for (j = 1; j < doomcom.numnodes; ++j)
			{
				if (nodeingame[j] && nettics[j] < lowtic && j != i)
				{
					lowtic = nettics[j];
				}
			}
			netbuffer[k++] = lowtic;
		}

		numtics = std::max(0, lowtic - realstart);
		if (numtics > BACKUPTICS)
			I_Error ("NetUpdate: Node %d missed too many tics", i);

		switch (net_extratic)
		{
		case 0:
		default: 
			resendto[i] = lowtic; break;
		case 1: resendto[i] = std::max(0, lowtic - 1); break;
		case 2: resendto[i] = nettics[i]; break;
		}

		if (numtics == 0 && resendOnly && !remoteresend[i] && nettics[i])
		{
			continue;
		}

		if (remoteresend[i])
		{
			netbuffer[0] |= NCMD_RETRANSMIT;
			netbuffer[k++] = nettics[i];
		}

		if (numtics < 3)
		{
			netbuffer[0] |= numtics;
		}
		else
		{
			netbuffer[0] |= NCMD_XTICS;
			netbuffer[k++] = numtics - 3;
		}

		if (quitcount > 0)
		{
			netbuffer[0] |= NCMD_QUITTERS;
			netbuffer[k++] = quitcount;
			for (int l = 0; l < doomcom.numnodes; ++l)
			{
				if (nodejustleft[l])
				{
					netbuffer[k++] = playerfornode[l];
				}
			}
		}

		// Send current network delay
		// The number of tics we just made should be removed from the count.
		netbuffer[k++] = ((maketic - numtics - gametic) / ticdup);

		if (numtics > 0)
		{
			int l;

			if (count > 1 && i != 0 && myconnectindex == Net_Arbitrator)
			{
				netbuffer[0] |= NCMD_MULTI;
				netbuffer[k++] = count;

				if (NetMode == NET_PacketServer)
				{
					for (l = 1, j = 0; j < MAXPLAYERS; j++)
					{
						if (playeringame[j] && j != playerfornode[i] && j != myconnectindex)
						{
							playerbytes[l++] = j;
							netbuffer[k++] = j;
						}
					}
				}
			}

			cmddata = &netbuffer[k];

			for (l = 0; l < count; ++l)
			{
				for (j = 0; j < numtics; j++)
				{
					int start = realstart + j, prev = start - 1;
					int localstart, localprev;

					localstart = (start * ticdup) % LOCALCMDTICS;
					localprev = (prev * ticdup) % LOCALCMDTICS;
					start %= BACKUPTICS;
					prev %= BACKUPTICS;

					// The local player has their tics sent first, followed by
					// the other players.
					if (l == 0)
					{
						WriteWord (localcmds[localstart].consistency, &cmddata);
						// [RH] Write out special "ticcmds" before real ticcmd
						if (specials.used[start])
						{
							memcpy (cmddata, specials.streams[start], specials.used[start]);
							cmddata += specials.used[start];
						}
						WriteUserCmdMessage (&localcmds[localstart].ucmd,
							localprev >= 0 ? &localcmds[localprev].ucmd : NULL, &cmddata);
					}
					else if (i != 0)
					{
						int len;
						uint8_t *spec;

						WriteWord (netcmds[playerbytes[l]][start].consistency, &cmddata);
						spec = NetSpecs[playerbytes[l]][start].GetData (&len);
						if (spec != NULL)
						{
							memcpy (cmddata, spec, len);
							cmddata += len;
						}

						WriteUserCmdMessage (&netcmds[playerbytes[l]][start].ucmd,
							prev >= 0 ? &netcmds[playerbytes[l]][prev].ucmd : NULL, &cmddata);
					}
				}
			}
			HSendPacket (i, int(cmddata - netbuffer));
		}
		else
		{
			HSendPacket (i, k);
		}
	}

	// listen for other packets
	GetPackets ();

	if (!resendOnly)
	{
		// ideally nettics[0] should be 1 - 3 tics above lowtic
		// if we are consistantly slower, speed up time

		// [RH] I had erroneously assumed frameskip[] had 4 entries
		// because there were 4 players, but that's not the case at
		// all. The game is comparing the lag behind the master for
		// four runs of TryRunTics. If our tic count is ahead of the
		// master all 4 times, the next run of NetUpdate will not
		// process any new input. If we have less input than the
		// master, the next run of NetUpdate will process extra tics
		// (because gametime gets decremented here).

		// the key player does not adapt
		if (myconnectindex != Net_Arbitrator)
		{
			// I'm not sure about this when using a packet server, because
			// if left unmodified from the P2P version, it can make the game
			// very jerky. The way I have it written right now basically means
			// that it won't adapt. Fortunately, player prediction helps
			// alleviate the lag somewhat.

			if (NetMode == NET_PeerToPeer)
			{
				int totalavg = 0;
				if (net_ticbalance)
				{
					// Try to guess ahead the time it takes to send responses to the slowest node
					int nodeavg = 0, arbavg = 0;

					for (j = 0; j < BACKUPTICS; j++)
					{
						arbavg += netdelay[nodeforplayer[Net_Arbitrator]][j];
						nodeavg += netdelay[0][j];
					}
					arbavg /= BACKUPTICS;
					nodeavg /= BACKUPTICS;

					// We shouldn't adapt if we are already the arbitrator isn't what we are waiting for, otherwise it just adds more latency
					if (arbavg > nodeavg)
					{
						lastaverage = totalavg = ((arbavg + nodeavg) / 2);
					}
					else
					{
						// Allow room to guess two tics ahead
						if (nodeavg > (arbavg + 2) && lastaverage > 0)
							lastaverage--;
						totalavg = lastaverage;
					}
				}
					
				mastertics = nettics[nodeforplayer[Net_Arbitrator]] + totalavg;
			}
			if (nettics[0] <= mastertics)
			{
				gametime--;
				if (debugfile) fprintf(debugfile, "-");
			}
			if (NetMode != NET_PacketServer)
			{
				frameskip[(maketic / ticdup) & 3] = (oldnettics > mastertics);
			}
			else
			{
				frameskip[(maketic / ticdup) & 3] = (oldnettics - mastertics) > 3;
			}
			if (frameskip[0] && frameskip[1] && frameskip[2] && frameskip[3])
			{
				skiptics = 1;
				if (debugfile) fprintf(debugfile, "+");
			}
			oldnettics = nettics[0];
		}
	}
}


//
// D_ArbitrateNetStart
//
// User info packets look like this:
//
//  0 One byte set to NCMD_SETUP or NCMD_SETUP+1; if NCMD_SETUP+1, omit byte 9
//  1 One byte for the player's number
//2-4 Three bytes for the game version (255,high byte,low byte)
//5-8 A bit mask for each player the sender knows about
//  9 The high bit is set if the sender got the game info
// 10 A stream of bytes with the user info
//
//    The guests always send NCMD_SETUP packets, and the host always
//    sends NCMD_SETUP+1 packets.
//
// Game info packets look like this:
//
//  0 One byte set to NCMD_SETUP+2
//  1 One byte for ticdup setting
//  2 One byte for NetMode setting
//  3 String with starting map's name
//  . Four bytes for the RNG seed
//  . Stream containing remaining game info
//
// Finished packet looks like this:
//
//  0 One byte set to NCMD_SETUP+3
//
// Each machine sends user info packets to the host. The host sends user
// info packets back to the other machines as well as game info packets.
// Negotiation is done when all the guests have reported to the host that
// they know about the other nodes.

struct ArbitrateData
{
	uint32_t playersdetected[MAXNETNODES];
	uint8_t  gotsetup[MAXNETNODES];
};

bool DoArbitrate (void *userdata)
{
	ArbitrateData *data = (ArbitrateData *)userdata;
	char *s;
	uint8_t *stream;
	int version;
	int node;
	int i, j;

	while (HGetPacket ())
	{
		if (netbuffer[0] == NCMD_EXIT)
		{
			I_FatalError ("The game was aborted.");
		}

		if (doomcom.remotenode == 0)
		{
			continue;
		}

		if (netbuffer[0] == NCMD_SETUP || netbuffer[0] == NCMD_SETUP+1)		// got user info
		{
			node = (netbuffer[0] == NCMD_SETUP) ? doomcom.remotenode : nodeforplayer[netbuffer[1]];

			data->playersdetected[node] =
				(netbuffer[5] << 24) | (netbuffer[6] << 16) | (netbuffer[7] << 8) | netbuffer[8];

			if (netbuffer[0] == NCMD_SETUP)
			{ // Sent to host
				data->gotsetup[node] = netbuffer[9] & 0x80;
				stream = &netbuffer[10];
			}
			else
			{ // Sent from host
				stream = &netbuffer[9];
			}

			D_ReadUserInfoStrings (netbuffer[1], &stream, false);
			if (!nodeingame[node])
			{
				version = (netbuffer[2] << 16) | (netbuffer[3] << 8) | netbuffer[4];
				if (version != (0xFF0000 | NETGAMEVERSION))
				{
					I_Error ("Different " GAMENAME " versions cannot play a net game");
				}

				playeringame[netbuffer[1]] = true;
				nodeingame[node] = true;

				data->playersdetected[0] |= 1 << netbuffer[1];

				StartScreen->NetMessage ("Found %s (node %d, player %d)", GetPlayerName(netbuffer[1]).GetChars(),
						node, netbuffer[1]+1);
			}
		}
		else if (netbuffer[0] == NCMD_SETUP+2)	// got game info
		{
			data->gotsetup[0] = 0x80;

			ticdup = doomcom.ticdup = netbuffer[1];
			NetMode = netbuffer[2];

			stream = &netbuffer[3];
			s = ReadString (&stream);
			startmap = s;
			delete[] s;
			rngseed = ReadLong (&stream);
			C_ReadCVars (&stream);
		}
		else if (netbuffer[0] == NCMD_SETUP+3)
		{
			return true;
		}
	}

	// If everybody already knows everything, it's time to go
	if (myconnectindex == Net_Arbitrator)
	{
		for (i = 0; i < doomcom.numnodes; ++i)
			if (data->playersdetected[i] != uint32_t(1 << doomcom.numnodes) - 1 || !data->gotsetup[i])
				break;

		if (i == doomcom.numnodes)
			return true;
	}

	netbuffer[2] = 255;
	netbuffer[3] = (NETGAMEVERSION >> 8) & 255;
	netbuffer[4] = NETGAMEVERSION & 255;
	netbuffer[5] = data->playersdetected[0] >> 24;
	netbuffer[6] = data->playersdetected[0] >> 16;
	netbuffer[7] = data->playersdetected[0] >> 8;
	netbuffer[8] = data->playersdetected[0];

	if (myconnectindex != Net_Arbitrator)
	{ // Send user info for the local node
		netbuffer[0] = NCMD_SETUP;
		netbuffer[1] = myconnectindex;
		netbuffer[9] = data->gotsetup[0];
		stream = &netbuffer[10];
		D_WriteUserInfoStrings (myconnectindex, &stream, true);
		SendSetup (data->playersdetected, data->gotsetup, int(stream - netbuffer));
	}
	else
	{ // Send user info for all nodes
		netbuffer[0] = NCMD_SETUP+1;
		for (i = 1; i < doomcom.numnodes; ++i)
		{
			for (j = 0; j < doomcom.numnodes; ++j)
			{
				// Send info about player j to player i?
				if ((data->playersdetected[0] & (1<<j)) && !(data->playersdetected[i] & (1<<j)))
				{
					netbuffer[1] = j;
					stream = &netbuffer[9];
					D_WriteUserInfoStrings (j, &stream, true);
					HSendPacket (i, int(stream - netbuffer));
				}
			}
		}
	}

	// If we're the host, send the game info, too
	if (myconnectindex == Net_Arbitrator)
	{
		netbuffer[0] = NCMD_SETUP+2;
		netbuffer[1] = (uint8_t)doomcom.ticdup;
		netbuffer[2] = NetMode;
		stream = &netbuffer[3];
		WriteString (startmap, &stream);
		WriteLong (rngseed, &stream);
		C_WriteCVars (&stream, CVAR_SERVERINFO, true);

		SendSetup (data->playersdetected, data->gotsetup, int(stream - netbuffer));
	}
	return false;
}

bool D_ArbitrateNetStart (void)
{
	ArbitrateData data;
	int i;

	// Return right away if we're just playing with ourselves.
	if (doomcom.numnodes == 1)
		return true;

	autostart = true;

	memset (data.playersdetected, 0, sizeof(data.playersdetected));
	memset (data.gotsetup, 0, sizeof(data.gotsetup));

	// The arbitrator knows about himself, but the other players must
	// be told about themselves, in case the host had to adjust their
	// userinfo (e.g. assign them to a different team).
	if (myconnectindex == Net_Arbitrator)
	{
		data.playersdetected[0] = 1 << myconnectindex;
	}

	// Assign nodes to players. The local player is always node 0.
	// If the local player is not the host, then the host is node 1.
	// Any remaining players are assigned node numbers in the order
	// they were detected.
	playerfornode[0] = myconnectindex;
	nodeforplayer[myconnectindex] = 0;
	if (myconnectindex == Net_Arbitrator)
	{
		for (i = 1; i < doomcom.numnodes; ++i)
		{
			playerfornode[i] = i;
			nodeforplayer[i] = i;
		}
	}
	else
	{
		playerfornode[1] = 0;
		nodeforplayer[0] = 1;
		for (i = 1; i < doomcom.numnodes; ++i)
		{
			if (i < myconnectindex)
			{
				playerfornode[i+1] = i;
				nodeforplayer[i] = i+1;
			}
			else if (i > myconnectindex)
			{
				playerfornode[i] = i;
				nodeforplayer[i] = i;
			}
		}
	}

	if (myconnectindex == Net_Arbitrator)
	{
		data.gotsetup[0] = 0x80;
	}

	StartScreen->NetInit ("Exchanging game information", 1);
	if (!StartScreen->NetLoop (DoArbitrate, &data))
	{
		return false;
	}

	if (myconnectindex == Net_Arbitrator)
	{
		netbuffer[0] = NCMD_SETUP+3;
		SendSetup (data.playersdetected, data.gotsetup, 1);
	}

	if (debugfile)
	{
		for (i = 0; i < doomcom.numnodes; ++i)
		{
			fprintf (debugfile, "player %d is on node %d\n", i, nodeforplayer[i]);
		}
	}
	StartScreen->NetDone();
	return true;
}

static void SendSetup (uint32_t playersdetected[MAXNETNODES], uint8_t gotsetup[MAXNETNODES], int len)
{
	if (myconnectindex != Net_Arbitrator)
	{
		if (playersdetected[1] & (1 << myconnectindex))
		{
			HSendPacket (1, 10);
		}
		else
		{
			HSendPacket (1, len);
		}
	}
	else
	{
		for (int i = 1; i < doomcom.numnodes; ++i)
		{
			if (!gotsetup[i] || netbuffer[0] == NCMD_SETUP+3)
			{
				HSendPacket (i, len);
			}
		}
	}
}

//
// D_CheckNetGame
// Works out player numbers among the net participants
//

bool D_CheckNetGame (void)
{
	const char *v;
	int i;

	// First install the global net command handlers

	Net_SetCommandHandler(DEM_GENERICCHEAT, genericCheat);
	Net_SetCommandHandler(DEM_CHANGEMAP, changeMap);
	Net_SetCommandHandler(DEM_ENDSCREENJOB, endScreenJob);

	for (i = 0; i < MAXNETNODES; i++)
	{
		nodeingame[i] = false;
		nettics[i] = 0;
		remoteresend[i] = false;		// set when local needs tics
		resendto[i] = 0;				// which tic to start sending
	}

	// Packet server has proven to be rather slow over the internet. Print a warning about it.
	v = Args->CheckValue("-netmode");
	if (v != NULL && (atoi(v) != 0))
	{
		Printf(TEXTCOLOR_YELLOW "Notice: Using PacketServer (netmode 1) over the internet is prone to running too slow on some internet configurations."
			"\nIf the game is running well below expected speeds, use netmode 0 (P2P) instead.\n");
	}

	int result = I_InitNetwork ();
	// I_InitNetwork sets doomcom and netgame
	if (result == -1)
	{
		return false;
	}
	else if (result > 0)
	{
		// For now, stop auto selecting PacketServer, as it's more likely to cause confusion.
		//NetMode = NET_PacketServer;
	}
	if (doomcom.id != DOOMCOM_ID)
	{
		I_FatalError ("Doomcom buffer invalid!");
	}
#if 0
	players[0].settings_controller = true;
#endif

	myconnectindex = doomcom.consoleplayer;

	if (myconnectindex == Net_Arbitrator)
	{
		v = Args->CheckValue("-netmode");
		if (v != NULL)
		{
			NetMode = atoi(v) != 0 ? NET_PacketServer : NET_PeerToPeer;
		}
		if (doomcom.numnodes > 1)
		{
			Printf("Selected " TEXTCOLOR_BLUE "%s" TEXTCOLOR_NORMAL " networking mode. (%s)\n", NetMode == NET_PeerToPeer ? "peer to peer" : "packet server",
				v != NULL ? "forced" : "auto");
		}

		if (Args->CheckParm("-extratic"))
		{
			net_extratic = 1;
		}
	}

#if 0
	// [RH] Setup user info
	D_SetupUserInfo ();
#endif

	if (Args->CheckParm ("-debugfile"))
	{
		char filename[20];
		mysnprintf (filename, countof(filename), "debug%i.txt", myconnectindex);
		Printf ("debug output to: %s\n", filename);
		debugfile = fopen (filename, "w");
	}

	if (netgame)
	{
		GameConfig->ReadNetVars ();	// [RH] Read network ServerInfo cvars
		if (!D_ArbitrateNetStart ()) return false;
	}

	// read values out of doomcom
	ticdup = doomcom.ticdup;

	for (i = 0; i < doomcom.numplayers; i++)
		playeringame[i] = true;
	for (i = 0; i < doomcom.numnodes; i++)
		nodeingame[i] = true;

	if (myconnectindex != Net_Arbitrator && doomcom.numnodes > 1)
	{
		Printf(PRINT_NONOTIFY, "Arbitrator selected " TEXTCOLOR_BLUE "%s" TEXTCOLOR_NORMAL " networking mode.\n", NetMode == NET_PeerToPeer ? "peer to peer" : "packet server");
	}

	if (!batchrun) Printf (PRINT_NONOTIFY, "player %i of %i (%i nodes)\n",
			myconnectindex+1, doomcom.numplayers, doomcom.numnodes);
	
	return true;
}


//
// D_QuitNetGame
// Called before quitting to leave a net game
// without hanging the other players
//
void D_QuitNetGame (void)
{
	int i, j, k;

	if (!netgame || !usergame || myconnectindex == -1 || demoplayback)
		return;

	// send a bunch of packets for security
	netbuffer[0] = NCMD_EXIT;
	netbuffer[1] = 0;

	k = 2;
	if (NetMode == NET_PacketServer && myconnectindex == Net_Arbitrator)
	{
		uint8_t *foo = &netbuffer[2];

		// Let the new arbitrator know what resendto counts to use

		for (i = 0; i < MAXPLAYERS; ++i)
		{
			if (playeringame[i] && i != myconnectindex)
				WriteLong (resendto[nodeforplayer[i]], &foo);
		}
		k = int(foo - netbuffer);
	}

	for (i = 0; i < 4; i++)
	{
		if (NetMode == NET_PacketServer && myconnectindex != Net_Arbitrator)
		{
			HSendPacket (nodeforplayer[Net_Arbitrator], 2);
		}
		else
		{
			for (j = 1; j < doomcom.numnodes; j++)
				if (nodeingame[j])
					HSendPacket (j, k);
		}
		I_WaitVBL (1);
	}

	if (debugfile)
		fclose (debugfile);
}


void Net_CheckLastReceived (int counts)
{
#if 0
	// [Ed850] Check to see the last time a packet was received.
	// If it's longer then 3 seconds, a node has likely stalled.
	if (I_GetTime() - lastglobalrecvtime >= GameTicRate * 3)
	{
		lastglobalrecvtime = I_GetTime(); //Bump the count

		if (NetMode == NET_PeerToPeer || myconnectindex == Net_Arbitrator)
		{
			//Keep the local node in the for loop so we can still log any cases where the local node is /somehow/ late.
			//However, we don't send a resend request for sanity reasons.
			for (int i = 0; i < doomcom.numnodes; i++)
			{
				if (nodeingame[i] && nettics[i] <= gametic + counts)
				{
					#
					if (debugfile && !players[playerfornode[i]].waiting)
						fprintf(debugfile, "%i is slow (%i to %i)\n",
						i, nettics[i], gametic + counts);
					//Send resend request to the late node. Also mark the node as waiting to display it in the hud.
					if (i != 0)
						remoteresend[i] = players[playerfornode[i]].waiting = hadlate = true;
				}
				else
					players[playerfornode[i]].waiting = false;
			}
		}
		else
		{	//Send a resend request to the Arbitrator, as it's obvious we are stuck here.
			if (debugfile && !players[Net_Arbitrator].waiting)
				fprintf(debugfile, "Arbitrator is slow (%i to %i)\n",
				nettics[nodeforplayer[Net_Arbitrator]], gametic + counts);
			//Send resend request to the Arbitrator. Also mark the Arbitrator as waiting to display it in the hud.
			remoteresend[nodeforplayer[Net_Arbitrator]] = players[Net_Arbitrator].waiting = hadlate = true;
		}
	}
#endif
}

void Net_NewMakeTic (void)
{
	specials.NewMakeTic ();
}

void Net_WriteByte (uint8_t it)
{
	specials << it;
}

void Net_WriteWord (short it)
{
	specials << it;
}

void Net_WriteLong (int it)
{
	specials << it;
}

void Net_WriteFloat (float it)
{
	specials << it;
}

void Net_WriteString (const char *it)
{
	specials << it;
}

void Net_WriteBytes (const uint8_t *block, int len)
{
	while (len--)
		specials << *block++;
}

//==========================================================================
//
// Dynamic buffer interface
//
//==========================================================================

FDynamicBuffer::FDynamicBuffer ()
{
	m_Data = NULL;
	m_Len = m_BufferLen = 0;
}

FDynamicBuffer::~FDynamicBuffer ()
{
	if (m_Data)
	{
		M_Free (m_Data);
		m_Data = NULL;
	}
	m_Len = m_BufferLen = 0;
}

void FDynamicBuffer::SetData (const uint8_t *data, int len)
{
	if (len > m_BufferLen)
	{
		m_BufferLen = (len + 255) & ~255;
		m_Data = (uint8_t *)M_Realloc (m_Data, m_BufferLen);
	}
	if (data != NULL)
	{
		m_Len = len;
		memcpy (m_Data, data, len);
	}
	else 
	{
		m_Len = 0;
	}
}

uint8_t *FDynamicBuffer::GetData (int *len)
{
	if (len)
		*len = m_Len;
	return m_Len ? m_Data : NULL;
}


NetCommandHandler nethandlers[DEM_MAX];

void Net_SetCommandHandler(EDemoCommand cmd, NetCommandHandler handler) noexcept
{
	assert(cmd >= 0 && cmd < DEM_MAX);
	if (cmd >= 0 && cmd < DEM_MAX) nethandlers[cmd] = handler;
}

// [RH] Execute a special "ticcmd". The type byte should
//		have already been read, and the stream is positioned
//		at the beginning of the command's actual data.
void Net_DoCommand (int cmd, uint8_t **stream, int player)
{
	assert(cmd >= 0 && cmd < DEM_MAX);
	if (cmd >= 0 && cmd < DEM_MAX && nethandlers[cmd])
	{
		nethandlers[cmd](player, stream, false);
	}
	else
		I_Error("Unknown net command: %d", cmd);
}


void Net_SkipCommand (int cmd, uint8_t **stream)
{
	if (cmd >= 0 && cmd < DEM_MAX && nethandlers[cmd])
	{
		nethandlers[cmd](0, stream, true);
	}
}

// Reset the network ticker after finishing a lengthy operation.
// Q: How does this affect network sync? Only allowed in SP games?
void Net_ClearFifo(void)
{
	I_SetFrameTime();
	gametime = I_GetTime();
}


// This was taken out of shared_hud, because UI code shouldn't do low level calculations that may change if the backing implementation changes.
int Net_GetLatency(int *ld, int *ad)
{
	int i, localdelay = 0, arbitratordelay = 0;

	for (i = 0; i < BACKUPTICS; i++) localdelay += netdelay[0][i];
	for (i = 0; i < BACKUPTICS; i++) arbitratordelay += netdelay[nodeforplayer[Net_Arbitrator]][i];
	arbitratordelay = ((arbitratordelay / BACKUPTICS) * ticdup) * (1000 / GameTicRate);
	localdelay = ((localdelay / BACKUPTICS) * ticdup) * (1000 / GameTicRate);
	int severity = 0;

	if (std::max(localdelay, arbitratordelay) > 200)
	{
		severity = 1;
	}
	if (std::max(localdelay, arbitratordelay) > 400)
	{
		severity = 2;
	}
	if (std::max(localdelay, arbitratordelay) >= ((BACKUPTICS / 2 - 1) * ticdup) * (1000 / GameTicRate))
	{
		severity = 3;
	}
	*ld = localdelay;
	*ad = arbitratordelay;
	return severity;
}

// [RH] List "ping" times
CCMD (pings)
{
	int i;
	for (i = 0; i < MAXPLAYERS; i++)
		if (playeringame[i])
			Printf("% 4" PRId64 " %s\n", currrecvtime[i] - lastrecvtime[i], GetPlayerName(i).GetChars());
}

//==========================================================================
//
// Network_Controller
//
// Implement players who have the ability to change settings in a network
// game.
//
//==========================================================================

static void Network_Controller (int playernum, bool add)
{
#if 0
	if (myconnectindex != Net_Arbitrator)
	{
		Printf ("This command is only accessible to the net arbitrator.\n");
		return;
	}

	if (players[playernum].settings_controller && add)
	{
		Printf ("%s is already on the setting controller list.\n", players[playernum].userinfo.GetName());
		return;
	}

	if (!players[playernum].settings_controller && !add)
	{
		Printf ("%s is not on the setting controller list.\n", players[playernum].userinfo.GetName());
		return;
	}

	if (!playeringame[playernum])
	{
		Printf ("Player (%d) not found!\n", playernum);
		return;
	}

	if (players[playernum].Bot != NULL)
	{
		Printf ("Bots cannot be added to the controller list.\n");
		return;
	}

	if (playernum == Net_Arbitrator)
	{
		Printf ("The net arbitrator cannot have their status changed on this list.\n");
		return;
	}

	if (add)
		Net_WriteByte (DEM_ADDCONTROLLER);
	else
		Net_WriteByte (DEM_DELCONTROLLER);

	Net_WriteByte (playernum);
#endif
}

//==========================================================================
//
// CCMD net_addcontroller
//
//==========================================================================

CCMD (net_addcontroller)
{
	if (!netgame)
	{
		Printf ("This command can only be used when playing a net game.\n");
		return;
	}

	if (argv.argc () < 2)
	{
		Printf ("Usage: net_addcontroller <player>\n");
		return;
	}

	Network_Controller (atoi (argv[1]), true);
}

//==========================================================================
//
// CCMD net_removecontroller
//
//==========================================================================

CCMD (net_removecontroller)
{
	if (!netgame)
	{
		Printf ("This command can only be used when playing a net game.\n");
		return;
	}

	if (argv.argc () < 2)
	{
		Printf ("Usage: net_removecontroller <player>\n");
		return;
	}

	Network_Controller (atoi (argv[1]), false);
}

//==========================================================================
//
// CCMD net_listcontrollers
//
//==========================================================================

CCMD (net_listcontrollers)
{
#if 0
	if (!netgame)
	{
		Printf ("This command can only be used when playing a net game.\n");
		return;
	}

	Printf ("The following players can change the game settings:\n");

	for (int i = 0; i < MAXPLAYERS; i++)
	{
		if (!playeringame[i])
			continue;

		if (players[i].settings_controller)
		{
			Printf ("- %s\n", players[i].userinfo.GetName());
		}
	}
#endif
}