quakeforge/nq/source/net_dgrm.c

/*
	net_dgrm.c

	@description@

	Copyright (C) 1996-1997  Id Software, Inc.

	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 2
	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, write to:

		Free Software Foundation, Inc.
		59 Temple Place - Suite 330
		Boston, MA  02111-1307, USA

	$Id$
*/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#ifdef HAVE_STRING_H
# include <string.h>
#endif
#ifdef HAVE_STRINGS_H
# include <strings.h>
#endif

#include "QF/cmd.h"
#include "QF/cvar.h"
#include "QF/sys.h"
#include "QF/keys.h"
#include "QF/qendian.h"
#include "QF/msg.h"
#include "QF/qargs.h"
#include "QF/screen.h"
#include "QF/console.h"

#include "client.h"
#include "server.h"
#include "net.h"
#include "game.h"
#include "sv_progs.h"

// This is enables a simple IP banning mechanism
#define BAN_TEST

#ifdef BAN_TEST
#if defined(_WIN32)
#include <windows.h>
#elif defined (NeXT)
#include <sys/socket.h>
#include <arpa/inet.h>
#else
#define AF_INET 		2				/* internet */
struct in_addr {
	union {
		struct {
			unsigned char s_b1, s_b2, s_b3, s_b4;
		} S_un_b;
		struct {
			unsigned short s_w1, s_w2;
		} S_un_w;
		unsigned long S_addr;
	} S_un;
};

#define	s_addr	S_un.S_addr				/* can be used for most tcp & ip code 
										 */
struct sockaddr_in {
	short       sin_family;
	unsigned short sin_port;
	struct in_addr sin_addr;
	char        sin_zero[8];
};
char       *inet_ntoa (struct in_addr in);
unsigned long inet_addr (const char *cp);
#endif
#endif // BAN_TEST

#include "net_dgrm.h"

// these two macros are to make the code more readable
#define sfunc	net_landrivers[sock->landriver]
#define dfunc	net_landrivers[net_landriverlevel]

static int  net_landriverlevel;

/* statistic counters */
int         packetsSent = 0;
int         packetsReSent = 0;
int         packetsReceived = 0;
int         receivedDuplicateCount = 0;
int         shortPacketCount = 0;
int         droppedDatagrams;

static int  myDriverLevel;

struct {
	unsigned int length;
	unsigned int sequence;
	byte        data[MAX_DATAGRAM];
} packetBuffer;

// FIXME: MENUCODE
//extern int  m_return_state;
//extern int  m_state;
//extern qboolean m_return_onerror;
//extern char m_return_reason[32];


#ifdef DEBUG
char       *
StrAddr (struct qsockaddr *addr)
{
	static char buf[34];
	byte       *p = (byte *) addr;
	int         n;

	for (n = 0; n < 16; n++)
		snprintf (buf + n * 2, sizeof (buf + n * 2), "%02x", *p++);
	return buf;
}
#endif


#ifdef BAN_TEST
unsigned long banAddr = 0x00000000;
unsigned long banMask = 0xffffffff;

void
NET_Ban_f (void)
{
	char        addrStr[32];
	char        maskStr[32];
	void        (*print) (const char *fmt, ...);

	if (cmd_source == src_command) {
		if (!sv.active) {
			Cmd_ForwardToServer ();
			return;
		}
		print = Con_Printf;
	} else {
		if (*sv_globals.deathmatch
			&& !host_client->privileged) return;
		print = SV_ClientPrintf;
	}

	switch (Cmd_Argc ()) {
		case 1:
		if (((struct in_addr *) &banAddr)->s_addr) {
			strcpy (addrStr, inet_ntoa (*(struct in_addr *) &banAddr));
			strcpy (maskStr, inet_ntoa (*(struct in_addr *) &banMask));
			print ("Banning %s [%s]\n", addrStr, maskStr);
		} else
			print ("Banning not active\n");
		break;

		case 2:
		if (strcasecmp (Cmd_Argv (1), "off") == 0)
			banAddr = 0x00000000;
		else
			banAddr = inet_addr (Cmd_Argv (1));
		banMask = 0xffffffff;
		break;

		case 3:
		banAddr = inet_addr (Cmd_Argv (1));
		banMask = inet_addr (Cmd_Argv (2));
		break;

		default:
		print ("BAN ip_address [mask]\n");
		break;
	}
}
#endif


int
Datagram_SendMessage (qsocket_t * sock, sizebuf_t *data)
{
	unsigned int packetLen;
	unsigned int dataLen;
	unsigned int eom;

#ifdef DEBUG
	if (data->cursize == 0)
		Sys_Error ("Datagram_SendMessage: zero length message\n");

	if (data->cursize > NET_MAXMESSAGE)
		Sys_Error ("Datagram_SendMessage: message too big %u\n", data->cursize);

	if (sock->canSend == false)
		Sys_Error ("SendMessage: called with canSend == false\n");
#endif

	memcpy (sock->sendMessage, data->data, data->cursize);
	sock->sendMessageLength = data->cursize;

	if (data->cursize <= MAX_DATAGRAM) {
		dataLen = data->cursize;
		eom = NETFLAG_EOM;
	} else {
		dataLen = MAX_DATAGRAM;
		eom = 0;
	}
	packetLen = NET_HEADERSIZE + dataLen;

	packetBuffer.length = BigLong (packetLen | (NETFLAG_DATA | eom));
	packetBuffer.sequence = BigLong (sock->sendSequence++);
	memcpy (packetBuffer.data, sock->sendMessage, dataLen);

	sock->canSend = false;

	if (sfunc.Write (sock->socket, (byte *) & packetBuffer, packetLen,
					 &sock->addr) == -1)
		return -1;

	sock->lastSendTime = net_time;
	packetsSent++;
	return 1;
}


int
SendMessageNext (qsocket_t * sock)
{
	unsigned int packetLen;
	unsigned int dataLen;
	unsigned int eom;

	if (sock->sendMessageLength <= MAX_DATAGRAM) {
		dataLen = sock->sendMessageLength;
		eom = NETFLAG_EOM;
	} else {
		dataLen = MAX_DATAGRAM;
		eom = 0;
	}
	packetLen = NET_HEADERSIZE + dataLen;

	packetBuffer.length = BigLong (packetLen | (NETFLAG_DATA | eom));
	packetBuffer.sequence = BigLong (sock->sendSequence++);
	memcpy (packetBuffer.data, sock->sendMessage, dataLen);

	sock->sendNext = false;

	if (sfunc.Write (sock->socket, (byte *) & packetBuffer, packetLen,
					 &sock->addr) == -1)
		return -1;

	sock->lastSendTime = net_time;
	packetsSent++;
	return 1;
}


int
ReSendMessage (qsocket_t * sock)
{
	unsigned int packetLen;
	unsigned int dataLen;
	unsigned int eom;

	if (sock->sendMessageLength <= MAX_DATAGRAM) {
		dataLen = sock->sendMessageLength;
		eom = NETFLAG_EOM;
	} else {
		dataLen = MAX_DATAGRAM;
		eom = 0;
	}
	packetLen = NET_HEADERSIZE + dataLen;

	packetBuffer.length = BigLong (packetLen | (NETFLAG_DATA | eom));
	packetBuffer.sequence = BigLong (sock->sendSequence - 1);
	memcpy (packetBuffer.data, sock->sendMessage, dataLen);

	sock->sendNext = false;

	if (sfunc.Write (sock->socket, (byte *) & packetBuffer, packetLen,
					 &sock->addr) == -1)
		return -1;

	sock->lastSendTime = net_time;
	packetsReSent++;
	return 1;
}


qboolean
Datagram_CanSendMessage (qsocket_t * sock)
{
	if (sock->sendNext)
		SendMessageNext (sock);

	return sock->canSend;
}


qboolean
Datagram_CanSendUnreliableMessage (qsocket_t * sock)
{
	return true;
}


int
Datagram_SendUnreliableMessage (qsocket_t * sock, sizebuf_t *data)
{
	int         packetLen;

#ifdef DEBUG
	if (data->cursize == 0)
		Sys_Error ("Datagram_SendUnreliableMessage: zero length message\n");

	if (data->cursize > MAX_DATAGRAM)
		Sys_Error ("Datagram_SendUnreliableMessage: message too big %u\n",
				   data->cursize);
#endif

	packetLen = NET_HEADERSIZE + data->cursize;

	packetBuffer.length = BigLong (packetLen | NETFLAG_UNRELIABLE);
	packetBuffer.sequence = BigLong (sock->unreliableSendSequence++);
	memcpy (packetBuffer.data, data->data, data->cursize);

	if (sfunc.Write (sock->socket, (byte *) & packetBuffer, packetLen,
					 &sock->addr) == -1)
		return -1;

	packetsSent++;
	return 1;
}


int
Datagram_GetMessage (qsocket_t * sock)
{
	unsigned int length;
	unsigned int flags;
	int         ret = 0;
	struct qsockaddr readaddr;
	unsigned int sequence;
	unsigned int count;

	if (!sock->canSend)
		if ((net_time - sock->lastSendTime) > 1.0)
			ReSendMessage (sock);

	while (1) {
		length =
			sfunc.Read (sock->socket, (byte *) & packetBuffer, NET_DATAGRAMSIZE,
						&readaddr);

//  if ((rand() & 255) > 220)
//      continue;

		if (length == 0)
			break;

		if (length == -1) {
			Con_Printf ("Read error\n");
			return -1;
		}

		if (sfunc.AddrCompare (&readaddr, &sock->addr) != 0) {
#ifdef DEBUG
			Con_DPrintf ("Forged packet received\n");
			Con_DPrintf ("Expected: %s\n", StrAddr (&sock->addr));
			Con_DPrintf ("Received: %s\n", StrAddr (&readaddr));
#endif
			continue;
		}

		if (length < NET_HEADERSIZE) {
			shortPacketCount++;
			continue;
		}

		length = BigLong (packetBuffer.length);
		flags = length & (~NETFLAG_LENGTH_MASK);
		length &= NETFLAG_LENGTH_MASK;

		if (flags & NETFLAG_CTL)
			continue;

		sequence = BigLong (packetBuffer.sequence);
		packetsReceived++;

		if (flags & NETFLAG_UNRELIABLE) {
			if (sequence < sock->unreliableReceiveSequence) {
				Con_DPrintf ("Got a stale datagram\n");
				ret = 0;
				break;
			}
			if (sequence != sock->unreliableReceiveSequence) {
				count = sequence - sock->unreliableReceiveSequence;
				droppedDatagrams += count;
				Con_DPrintf ("Dropped %u datagram(s)\n", count);
			}
			sock->unreliableReceiveSequence = sequence + 1;

			length -= NET_HEADERSIZE;

			SZ_Clear (net_message->message);
			SZ_Write (net_message->message, packetBuffer.data, length);

			ret = 2;
			break;
		}

		if (flags & NETFLAG_ACK) {
			if (sequence != (sock->sendSequence - 1)) {
				Con_DPrintf ("Stale ACK received\n");
				continue;
			}
			if (sequence == sock->ackSequence) {
				sock->ackSequence++;
				if (sock->ackSequence != sock->sendSequence)
					Con_DPrintf ("ack sequencing error\n");
			} else {
				Con_DPrintf ("Duplicate ACK received\n");
				continue;
			}
			sock->sendMessageLength -= MAX_DATAGRAM;
			if (sock->sendMessageLength > 0) {
				memcpy (sock->sendMessage, sock->sendMessage + MAX_DATAGRAM,
						sock->sendMessageLength);
				sock->sendNext = true;
			} else {
				sock->sendMessageLength = 0;
				sock->canSend = true;
			}
			continue;
		}

		if (flags & NETFLAG_DATA) {
			packetBuffer.length = BigLong (NET_HEADERSIZE | NETFLAG_ACK);
			packetBuffer.sequence = BigLong (sequence);
			sfunc.Write (sock->socket, (byte *) & packetBuffer, NET_HEADERSIZE,
						 &readaddr);

			if (sequence != sock->receiveSequence) {
				receivedDuplicateCount++;
				continue;
			}
			sock->receiveSequence++;

			length -= NET_HEADERSIZE;

			if (flags & NETFLAG_EOM) {
				SZ_Clear (net_message->message);
				SZ_Write (net_message->message, sock->receiveMessage,
						  sock->receiveMessageLength);
				SZ_Write (net_message->message, packetBuffer.data, length);
				sock->receiveMessageLength = 0;

				ret = 1;
				break;
			}

			memcpy (sock->receiveMessage + sock->receiveMessageLength,
					packetBuffer.data, length);
			sock->receiveMessageLength += length;
			continue;
		}
	}

	if (sock->sendNext)
		SendMessageNext (sock);

	return ret;
}


void
PrintStats (qsocket_t * s)
{
	Con_Printf ("canSend = %4u   \n", s->canSend);
	Con_Printf ("sendSeq = %4u   ", s->sendSequence);
	Con_Printf ("recvSeq = %4u   \n", s->receiveSequence);
	Con_Printf ("\n");
}

void
NET_Stats_f (void)
{
	qsocket_t  *s;

	if (Cmd_Argc () == 1) {
		Con_Printf ("unreliable messages sent   = %i\n",
					unreliableMessagesSent);
		Con_Printf ("unreliable messages recv   = %i\n",
					unreliableMessagesReceived);
		Con_Printf ("reliable messages sent     = %i\n", messagesSent);
		Con_Printf ("reliable messages received = %i\n", messagesReceived);
		Con_Printf ("packetsSent                = %i\n", packetsSent);
		Con_Printf ("packetsReSent              = %i\n", packetsReSent);
		Con_Printf ("packetsReceived            = %i\n", packetsReceived);
		Con_Printf ("receivedDuplicateCount     = %i\n",
					receivedDuplicateCount);
		Con_Printf ("shortPacketCount           = %i\n", shortPacketCount);
		Con_Printf ("droppedDatagrams           = %i\n", droppedDatagrams);
	} else if (strcmp (Cmd_Argv (1), "*") == 0) {
		for (s = net_activeSockets; s; s = s->next)
			PrintStats (s);
		for (s = net_freeSockets; s; s = s->next)
			PrintStats (s);
	} else {
		for (s = net_activeSockets; s; s = s->next)
			if (strcasecmp (Cmd_Argv (1), s->address) == 0)
				break;
		if (s == NULL)
			for (s = net_freeSockets; s; s = s->next)
				if (strcasecmp (Cmd_Argv (1), s->address) == 0)
					break;
		if (s == NULL)
			return;
		PrintStats (s);
	}
}


static qboolean testInProgress = false;
static int  testPollCount;
static int  testDriver;
static int  testSocket;

static void Test_Poll (void);
PollProcedure testPollProcedure = { NULL, 0.0, Test_Poll };

static void
Test_Poll (void)
{
	struct qsockaddr clientaddr;
	int         control;
	int         len;
	char        name[32];
	char        address[64];
	int         colors;
	int         frags;
	int         connectTime;
	byte        playerNumber;

	net_landriverlevel = testDriver;

	while (1) {
		len =
			dfunc.Read (testSocket, net_message->message->data,
						net_message->message->maxsize, &clientaddr);
		if (len < sizeof (int))
			break;

		net_message->message->cursize = len;

		MSG_BeginReading (net_message);
		control = BigLong (*((int *) net_message->message->data));
		MSG_ReadLong (net_message);
		if (control == -1)
			break;
		if ((control & (~NETFLAG_LENGTH_MASK)) != NETFLAG_CTL)
			break;
		if ((control & NETFLAG_LENGTH_MASK) != len)
			break;

		if (MSG_ReadByte (net_message) != CCREP_PLAYER_INFO)
			Sys_Error ("Unexpected repsonse to Player Info request\n");

		playerNumber = MSG_ReadByte (net_message);
		strcpy (name, MSG_ReadString (net_message));
		colors = MSG_ReadLong (net_message);
		frags = MSG_ReadLong (net_message);
		connectTime = MSG_ReadLong (net_message);
		strcpy (address, MSG_ReadString (net_message));

		Con_Printf ("%s\n  frags:%3i  colors:%u %u  time:%u\n  %s\n", name,
					frags, colors >> 4, colors & 0x0f, connectTime / 60,
					address);
	}

	testPollCount--;
	if (testPollCount) {
		SchedulePollProcedure (&testPollProcedure, 0.1);
	} else {
		dfunc.CloseSocket (testSocket);
		testInProgress = false;
	}
}

static void
Test_f (void)
{
	const char *host;
	int         n;
	int         max = MAX_SCOREBOARD;
	struct qsockaddr sendaddr;

	if (testInProgress)
		return;

	host = Cmd_Argv (1);

	if (host && hostCacheCount) {
		for (n = 0; n < hostCacheCount; n++)
			if (strcasecmp (host, hostcache[n].name) == 0) {
				if (hostcache[n].driver != myDriverLevel)
					continue;
				net_landriverlevel = hostcache[n].ldriver;
				max = hostcache[n].maxusers;
				memcpy (&sendaddr, &hostcache[n].addr,

						sizeof (struct qsockaddr));
				break;
			}
		if (n < hostCacheCount)
			goto JustDoIt;
	}

	for (net_landriverlevel = 0; net_landriverlevel < net_numlandrivers;
		 net_landriverlevel++) {
		if (!net_landrivers[net_landriverlevel].initialized)
			continue;

		// see if we can resolve the host name
		if (dfunc.GetAddrFromName (host, &sendaddr) != -1)
			break;
	}
	if (net_landriverlevel == net_numlandrivers)
		return;

  JustDoIt:
	testSocket = dfunc.OpenSocket (0);
	if (testSocket == -1)
		return;

	testInProgress = true;
	testPollCount = 20;
	testDriver = net_landriverlevel;

	for (n = 0; n < max; n++) {
		SZ_Clear (net_message->message);
		// save space for the header, filled in later
		MSG_WriteLong (net_message->message, 0);
		MSG_WriteByte (net_message->message, CCREQ_PLAYER_INFO);
		MSG_WriteByte (net_message->message, n);
		*((int *) net_message->message->data) =
			BigLong (NETFLAG_CTL |
					 (net_message->message->cursize & NETFLAG_LENGTH_MASK));
		dfunc.Write (testSocket, net_message->message->data,
					 net_message->message->cursize, &sendaddr);
	}
	SZ_Clear (net_message->message);
	SchedulePollProcedure (&testPollProcedure, 0.1);
}


static qboolean test2InProgress = false;
static int  test2Driver;
static int  test2Socket;

static void Test2_Poll (void);
PollProcedure test2PollProcedure = { NULL, 0.0, Test2_Poll };

static void
Test2_Poll (void)
{
	struct qsockaddr clientaddr;
	int         control;
	int         len;
	char        name[256];
	char        value[256];

	net_landriverlevel = test2Driver;
	name[0] = 0;

	len =
		dfunc.Read (test2Socket, net_message->message->data,
					net_message->message->maxsize, &clientaddr);
	if (len < sizeof (int))
		goto Reschedule;

	net_message->message->cursize = len;

	MSG_BeginReading (net_message);
	control = BigLong (*((int *) net_message->message->data));
	MSG_ReadLong (net_message);
	if (control == -1)
		goto Error;
	if ((control & (~NETFLAG_LENGTH_MASK)) != NETFLAG_CTL)
		goto Error;
	if ((control & NETFLAG_LENGTH_MASK) != len)
		goto Error;

	if (MSG_ReadByte (net_message) != CCREP_RULE_INFO)
		goto Error;

	strcpy (name, MSG_ReadString (net_message));
	if (name[0] == 0)
		goto Done;
	strcpy (value, MSG_ReadString (net_message));

	Con_Printf ("%-16.16s  %-16.16s\n", name, value);

	SZ_Clear (net_message->message);
	// save space for the header, filled in later
	MSG_WriteLong (net_message->message, 0);
	MSG_WriteByte (net_message->message, CCREQ_RULE_INFO);
	MSG_WriteString (net_message->message, name);
	*((int *) net_message->message->data) =
		BigLong (NETFLAG_CTL |
				 (net_message->message->cursize & NETFLAG_LENGTH_MASK));
	dfunc.Write (test2Socket, net_message->message->data,
				 net_message->message->cursize, &clientaddr);
	SZ_Clear (net_message->message);

  Reschedule:
	SchedulePollProcedure (&test2PollProcedure, 0.05);
	return;

  Error:
	Con_Printf ("Unexpected repsonse to Rule Info request\n");
  Done:
	dfunc.CloseSocket (test2Socket);
	test2InProgress = false;
	return;
}

static void
Test2_f (void)
{
	const char *host;
	int         n;
	struct qsockaddr sendaddr;

	if (test2InProgress)
		return;

	host = Cmd_Argv (1);

	if (host && hostCacheCount) {
		for (n = 0; n < hostCacheCount; n++)
			if (strcasecmp (host, hostcache[n].name) == 0) {
				if (hostcache[n].driver != myDriverLevel)
					continue;
				net_landriverlevel = hostcache[n].ldriver;
				memcpy (&sendaddr, &hostcache[n].addr,

						sizeof (struct qsockaddr));
				break;
			}
		if (n < hostCacheCount)
			goto JustDoIt;
	}

	for (net_landriverlevel = 0; net_landriverlevel < net_numlandrivers;
		 net_landriverlevel++) {
		if (!net_landrivers[net_landriverlevel].initialized)
			continue;

		// see if we can resolve the host name
		if (dfunc.GetAddrFromName (host, &sendaddr) != -1)
			break;
	}
	if (net_landriverlevel == net_numlandrivers)
		return;

  JustDoIt:
	test2Socket = dfunc.OpenSocket (0);
	if (test2Socket == -1)
		return;

	test2InProgress = true;
	test2Driver = net_landriverlevel;

	SZ_Clear (net_message->message);
	// save space for the header, filled in later
	MSG_WriteLong (net_message->message, 0);
	MSG_WriteByte (net_message->message, CCREQ_RULE_INFO);
	MSG_WriteString (net_message->message, "");
	*((int *) net_message->message->data) =
		BigLong (NETFLAG_CTL |
				 (net_message->message->cursize & NETFLAG_LENGTH_MASK));
	dfunc.Write (test2Socket, net_message->message->data,
				 net_message->message->cursize, &sendaddr);
	SZ_Clear (net_message->message);
	SchedulePollProcedure (&test2PollProcedure, 0.05);
}


int
Datagram_Init (void)
{
	int         i;
	int         csock;

	myDriverLevel = net_driverlevel;
	Cmd_AddCommand ("net_stats", NET_Stats_f, "No Description");

	if (COM_CheckParm ("-nolan"))
		return -1;

	for (i = 0; i < net_numlandrivers; i++) {
		csock = net_landrivers[i].Init ();
		if (csock == -1)
			continue;
		net_landrivers[i].initialized = true;
		net_landrivers[i].controlSock = csock;
	}

#ifdef BAN_TEST
	Cmd_AddCommand ("ban", NET_Ban_f, "No Description");
#endif
	Cmd_AddCommand ("test", Test_f, "No Description");
	Cmd_AddCommand ("test2", Test2_f, "No Description");

	return 0;
}


void
Datagram_Shutdown (void)
{
	int         i;

//
// shutdown the lan drivers
//
	for (i = 0; i < net_numlandrivers; i++) {
		if (net_landrivers[i].initialized) {
			net_landrivers[i].Shutdown ();
			net_landrivers[i].initialized = false;
		}
	}
}


void
Datagram_Close (qsocket_t * sock)
{
	sfunc.CloseSocket (sock->socket);
}


void
Datagram_Listen (qboolean state)
{
	int         i;

	for (i = 0; i < net_numlandrivers; i++)
		if (net_landrivers[i].initialized)
			net_landrivers[i].Listen (state);
}


static qsocket_t *
_Datagram_CheckNewConnections (void)
{
	struct qsockaddr clientaddr;
	struct qsockaddr newaddr;
	int         newsock;
	int         acceptsock;
	qsocket_t  *sock;
	qsocket_t  *s;
	int         len;
	int         command;
	int         control;
	int         ret;

	acceptsock = dfunc.CheckNewConnections ();
	if (acceptsock == -1)
		return NULL;

	SZ_Clear (net_message->message);

	len =
		dfunc.Read (acceptsock, net_message->message->data,
					net_message->message->maxsize, &clientaddr);
	if (len < sizeof (int))
		return NULL;

	net_message->message->cursize = len;

	MSG_BeginReading (net_message);
	control = BigLong (*((int *) net_message->message->data));
	MSG_ReadLong (net_message);
	if (control == -1)
		return NULL;
	if ((control & (~NETFLAG_LENGTH_MASK)) != NETFLAG_CTL)
		return NULL;
	if ((control & NETFLAG_LENGTH_MASK) != len)
		return NULL;

	command = MSG_ReadByte (net_message);
	if (command == CCREQ_SERVER_INFO) {
		if (strcmp (MSG_ReadString (net_message), "QUAKE") != 0)
			return NULL;

		SZ_Clear (net_message->message);
		// save space for the header, filled in later
		MSG_WriteLong (net_message->message, 0);
		MSG_WriteByte (net_message->message, CCREP_SERVER_INFO);
		dfunc.GetSocketAddr (acceptsock, &newaddr);
		MSG_WriteString (net_message->message, dfunc.AddrToString (&newaddr));
		MSG_WriteString (net_message->message, hostname->string);
		MSG_WriteString (net_message->message, sv.name);
		MSG_WriteByte (net_message->message, net_activeconnections);
		MSG_WriteByte (net_message->message, svs.maxclients);
		MSG_WriteByte (net_message->message, NET_PROTOCOL_VERSION);
		*((int *) net_message->message->data) =
			BigLong (NETFLAG_CTL |
					 (net_message->message->cursize & NETFLAG_LENGTH_MASK));
		dfunc.Write (acceptsock, net_message->message->data,
					 net_message->message->cursize, &clientaddr);
		SZ_Clear (net_message->message);
		return NULL;
	}

	if (command == CCREQ_PLAYER_INFO) {
		int         playerNumber;
		int         activeNumber;
		int         clientNumber;
		client_t   *client;

		playerNumber = MSG_ReadByte (net_message);
		activeNumber = -1;
		for (clientNumber = 0, client = svs.clients;
			 clientNumber < svs.maxclients; clientNumber++, client++) {
			if (client->active) {
				activeNumber++;
				if (activeNumber == playerNumber)
					break;
			}
		}
		if (clientNumber == svs.maxclients)
			return NULL;

		SZ_Clear (net_message->message);
		// save space for the header, filled in later
		MSG_WriteLong (net_message->message, 0);
		MSG_WriteByte (net_message->message, CCREP_PLAYER_INFO);
		MSG_WriteByte (net_message->message, playerNumber);
		MSG_WriteString (net_message->message, client->name);
		MSG_WriteLong (net_message->message, client->colors);
		MSG_WriteLong (net_message->message, SVFIELD (client->edict, frags, float));
		MSG_WriteLong (net_message->message,
					   (int) (net_time - client->netconnection->connecttime));
		MSG_WriteString (net_message->message, client->netconnection->address);
		*((int *) net_message->message->data) =
			BigLong (NETFLAG_CTL |
					 (net_message->message->cursize & NETFLAG_LENGTH_MASK));
		dfunc.Write (acceptsock, net_message->message->data,
					 net_message->message->cursize, &clientaddr);
		SZ_Clear (net_message->message);

		return NULL;
	}

	if (command == CCREQ_RULE_INFO) {
		char       *prevCvarName;
		cvar_t     *var;

		// find the search start location
		prevCvarName = MSG_ReadString (net_message);
		if (*prevCvarName) {
			var = Cvar_FindVar (prevCvarName);
			if (!var)
				return NULL;
			var = var->next;
		} else
			var = cvar_vars;

		// search for the next server cvar
		while (var) {
			if (var->flags & CVAR_SERVERINFO)
				break;
			var = var->next;
		}

		// send the response

		SZ_Clear (net_message->message);
		// save space for the header, filled in later
		MSG_WriteLong (net_message->message, 0);
		MSG_WriteByte (net_message->message, CCREP_RULE_INFO);
		if (var) {
			MSG_WriteString (net_message->message, var->name);
			MSG_WriteString (net_message->message, var->string);
		}
		*((int *) net_message->message->data) =
			BigLong (NETFLAG_CTL |
					 (net_message->message->cursize & NETFLAG_LENGTH_MASK));
		dfunc.Write (acceptsock, net_message->message->data,
					 net_message->message->cursize, &clientaddr);
		SZ_Clear (net_message->message);

		return NULL;
	}

	if (command != CCREQ_CONNECT)
		return NULL;

	if (strcmp (MSG_ReadString (net_message), "QUAKE") != 0)
		return NULL;

	if (MSG_ReadByte (net_message) != NET_PROTOCOL_VERSION) {
		SZ_Clear (net_message->message);
		// save space for the header, filled in later
		MSG_WriteLong (net_message->message, 0);
		MSG_WriteByte (net_message->message, CCREP_REJECT);
		MSG_WriteString (net_message->message, "Incompatible version.\n");
		*((int *) net_message->message->data) =
			BigLong (NETFLAG_CTL |
					 (net_message->message->cursize & NETFLAG_LENGTH_MASK));
		dfunc.Write (acceptsock, net_message->message->data,
					 net_message->message->cursize, &clientaddr);
		SZ_Clear (net_message->message);
		return NULL;
	}
#ifdef BAN_TEST
	// check for a ban
	if (clientaddr.sa_family == AF_INET) {
		unsigned long testAddr;

		testAddr = ((struct sockaddr_in *) &clientaddr)->sin_addr.s_addr;
		if ((testAddr & banMask) == banAddr) {
			SZ_Clear (net_message->message);
			// save space for the header, filled in later
			MSG_WriteLong (net_message->message, 0);
			MSG_WriteByte (net_message->message, CCREP_REJECT);
			MSG_WriteString (net_message->message, "You have been banned.\n");
			*((int *) net_message->message->data) =
				BigLong (NETFLAG_CTL |
						 (net_message->message->cursize & NETFLAG_LENGTH_MASK));
			dfunc.Write (acceptsock, net_message->message->data,
						 net_message->message->cursize, &clientaddr);
			SZ_Clear (net_message->message);
			return NULL;
		}
	}
#endif

	// see if this guy is already connected
	for (s = net_activeSockets; s; s = s->next) {
		if (s->driver != net_driverlevel)
			continue;
		ret = dfunc.AddrCompare (&clientaddr, &s->addr);
		if (ret >= 0) {
			// is this a duplicate connection reqeust?
			if (ret == 0 && net_time - s->connecttime < 2.0) {
				// yes, so send a duplicate reply
				SZ_Clear (net_message->message);
				// save space for the header, filled in later
				MSG_WriteLong (net_message->message, 0);
				MSG_WriteByte (net_message->message, CCREP_ACCEPT);
				dfunc.GetSocketAddr (s->socket, &newaddr);
				MSG_WriteLong (net_message->message,
							   dfunc.GetSocketPort (&newaddr));
				*((int *) net_message->message->data) =
					BigLong (NETFLAG_CTL |
							 (net_message->
							  message->cursize & NETFLAG_LENGTH_MASK));
				dfunc.Write (acceptsock, net_message->message->data,
							 net_message->message->cursize, &clientaddr);
				SZ_Clear (net_message->message);
				return NULL;
			}
			// it's somebody coming back in from a crash/disconnect
			// so close the old qsocket and let their retry get them back in
			NET_Close (s);
			return NULL;
		}
	}

	// allocate a QSocket
	sock = NET_NewQSocket ();
	if (sock == NULL) {
		// no room; try to let him know
		SZ_Clear (net_message->message);
		// save space for the header, filled in later
		MSG_WriteLong (net_message->message, 0);
		MSG_WriteByte (net_message->message, CCREP_REJECT);
		MSG_WriteString (net_message->message, "Server is full.\n");
		*((int *) net_message->message->data) =
			BigLong (NETFLAG_CTL |
					 (net_message->message->cursize & NETFLAG_LENGTH_MASK));
		dfunc.Write (acceptsock, net_message->message->data,
					 net_message->message->cursize, &clientaddr);
		SZ_Clear (net_message->message);
		return NULL;
	}
	// allocate a network socket
	newsock = dfunc.OpenSocket (0);
	if (newsock == -1) {
		NET_FreeQSocket (sock);
		return NULL;
	}
	// connect to the client
	if (dfunc.Connect (newsock, &clientaddr) == -1) {
		dfunc.CloseSocket (newsock);
		NET_FreeQSocket (sock);
		return NULL;
	}
	// everything is allocated, just fill in the details    
	sock->socket = newsock;
	sock->landriver = net_landriverlevel;
	sock->addr = clientaddr;
	strcpy (sock->address, dfunc.AddrToString (&clientaddr));

	// send him back the info about the server connection he has been
	// allocated
	SZ_Clear (net_message->message);
	// save space for the header, filled in later
	MSG_WriteLong (net_message->message, 0);
	MSG_WriteByte (net_message->message, CCREP_ACCEPT);
	dfunc.GetSocketAddr (newsock, &newaddr);
	MSG_WriteLong (net_message->message, dfunc.GetSocketPort (&newaddr));
//  MSG_WriteString(net_message->message, dfunc.AddrToString(&newaddr));
	*((int *) net_message->message->data) =
		BigLong (NETFLAG_CTL |
				 (net_message->message->cursize & NETFLAG_LENGTH_MASK));
	dfunc.Write (acceptsock, net_message->message->data,
				 net_message->message->cursize, &clientaddr);
	SZ_Clear (net_message->message);

	return sock;
}

qsocket_t  *
Datagram_CheckNewConnections (void)
{
	qsocket_t  *ret = NULL;

	for (net_landriverlevel = 0; net_landriverlevel < net_numlandrivers;
		 net_landriverlevel++)
		if (net_landrivers[net_landriverlevel].initialized)
			if ((ret = _Datagram_CheckNewConnections ()) != NULL)
				break;
	return ret;
}


static void
_Datagram_SearchForHosts (qboolean xmit)
{
	int         ret;
	int         n;
	int         i;
	struct qsockaddr readaddr;
	struct qsockaddr myaddr;
	int         control;

	dfunc.GetSocketAddr (dfunc.controlSock, &myaddr);
	if (xmit) {
		SZ_Clear (net_message->message);
		// save space for the header, filled in later
		MSG_WriteLong (net_message->message, 0);
		MSG_WriteByte (net_message->message, CCREQ_SERVER_INFO);
		MSG_WriteString (net_message->message, "QUAKE");
		MSG_WriteByte (net_message->message, NET_PROTOCOL_VERSION);
		*((int *) net_message->message->data) =
			BigLong (NETFLAG_CTL |
					 (net_message->message->cursize & NETFLAG_LENGTH_MASK));
		dfunc.Broadcast (dfunc.controlSock, net_message->message->data,
						 net_message->message->cursize);
		SZ_Clear (net_message->message);
	}

	while (
		   (ret =
			dfunc.Read (dfunc.controlSock, net_message->message->data,
						net_message->message->maxsize, &readaddr)) > 0) {
		if (ret < sizeof (int))
			continue;

		net_message->message->cursize = ret;

		// don't answer our own query
		if (dfunc.AddrCompare (&readaddr, &myaddr) >= 0)
			continue;

		// is the cache full?
		if (hostCacheCount == HOSTCACHESIZE)
			continue;

		MSG_BeginReading (net_message);
		control = BigLong (*((int *) net_message->message->data));
		MSG_ReadLong (net_message);
		if (control == -1)
			continue;
		if ((control & (~NETFLAG_LENGTH_MASK)) != NETFLAG_CTL)
			continue;
		if ((control & NETFLAG_LENGTH_MASK) != ret)
			continue;

		if (MSG_ReadByte (net_message) != CCREP_SERVER_INFO)
			continue;

		dfunc.GetAddrFromName (MSG_ReadString (net_message), &readaddr);
		// search the cache for this server
		for (n = 0; n < hostCacheCount; n++)
			if (dfunc.AddrCompare (&readaddr, &hostcache[n].addr) == 0)
				break;

		// is it already there?
		if (n < hostCacheCount)
			continue;

		// add it
		hostCacheCount++;
		strcpy (hostcache[n].name, MSG_ReadString (net_message));
		strcpy (hostcache[n].map, MSG_ReadString (net_message));
		hostcache[n].users = MSG_ReadByte (net_message);
		hostcache[n].maxusers = MSG_ReadByte (net_message);
		if (MSG_ReadByte (net_message) != NET_PROTOCOL_VERSION) {
			strcpy (hostcache[n].cname, hostcache[n].name);
			hostcache[n].cname[14] = 0;
			strcpy (hostcache[n].name, "*");
			strcat (hostcache[n].name, hostcache[n].cname);
		}
		memcpy (&hostcache[n].addr, &readaddr, sizeof (struct qsockaddr));

		hostcache[n].driver = net_driverlevel;
		hostcache[n].ldriver = net_landriverlevel;
		strcpy (hostcache[n].cname, dfunc.AddrToString (&readaddr));

		// check for a name conflict
		for (i = 0; i < hostCacheCount; i++) {
			if (i == n)
				continue;
			if (strcasecmp (hostcache[n].name, hostcache[i].name) == 0) {
				i = strlen (hostcache[n].name);
				if (i < 15 && hostcache[n].name[i - 1] > '8') {
					hostcache[n].name[i] = '0';
					hostcache[n].name[i + 1] = 0;
				} else
					hostcache[n].name[i - 1]++;
				i = -1;
			}
		}
	}
}

void
Datagram_SearchForHosts (qboolean xmit)
{
	for (net_landriverlevel = 0; net_landriverlevel < net_numlandrivers;
		 net_landriverlevel++) {
		if (hostCacheCount == HOSTCACHESIZE)
			break;
		if (net_landrivers[net_landriverlevel].initialized)
			_Datagram_SearchForHosts (xmit);
	}
}


static qsocket_t *
_Datagram_Connect (const char *host)
{
	struct qsockaddr sendaddr;
	struct qsockaddr readaddr;
	qsocket_t  *sock;
	int         newsock;
	int         ret;
	int         reps;
	double      start_time;
	int         control;
	char       *reason;

	// see if we can resolve the host name
	if (dfunc.GetAddrFromName (host, &sendaddr) == -1)
		return NULL;

	newsock = dfunc.OpenSocket (0);
	if (newsock == -1)
		return NULL;

	sock = NET_NewQSocket ();
	if (sock == NULL)
		goto ErrorReturn2;
	sock->socket = newsock;
	sock->landriver = net_landriverlevel;

	// connect to the host
	if (dfunc.Connect (newsock, &sendaddr) == -1)
		goto ErrorReturn;

	// send the connection request
	Con_Printf ("trying...\n");
	CL_UpdateScreen (cl.time);
	start_time = net_time;

	for (reps = 0; reps < 3; reps++) {
		SZ_Clear (net_message->message);
		// save space for the header, filled in later
		MSG_WriteLong (net_message->message, 0);
		MSG_WriteByte (net_message->message, CCREQ_CONNECT);
		MSG_WriteString (net_message->message, "QUAKE");
		MSG_WriteByte (net_message->message, NET_PROTOCOL_VERSION);
		*((int *) net_message->message->data) =
			BigLong (NETFLAG_CTL |
					 (net_message->message->cursize & NETFLAG_LENGTH_MASK));
		dfunc.Write (newsock, net_message->message->data,
					 net_message->message->cursize, &sendaddr);
		SZ_Clear (net_message->message);
		do {
			ret =
				dfunc.Read (newsock, net_message->message->data,
							net_message->message->maxsize, &readaddr);
			// if we got something, validate it
			if (ret > 0) {
				// is it from the right place?
				if (sfunc.AddrCompare (&readaddr, &sendaddr) != 0) {
#ifdef DEBUG
					Con_Printf ("wrong reply address\n");
					Con_Printf ("Expected: %s\n", StrAddr (&sendaddr));
					Con_Printf ("Received: %s\n", StrAddr (&readaddr));
					CL_UpdateScreen (cl.time);
#endif
					ret = 0;
					continue;
				}

				if (ret < sizeof (int)) {
					ret = 0;
					continue;
				}

				net_message->message->cursize = ret;
				MSG_BeginReading (net_message);

				control = BigLong (*((int *) net_message->message->data));
				MSG_ReadLong (net_message);
				if (control == -1) {
					ret = 0;
					continue;
				}
				if ((control & (~NETFLAG_LENGTH_MASK)) != NETFLAG_CTL) {
					ret = 0;
					continue;
				}
				if ((control & NETFLAG_LENGTH_MASK) != ret) {
					ret = 0;
					continue;
				}
			}
		}
		while (ret == 0 && (SetNetTime () - start_time) < 2.5);
		if (ret)
			break;
		Con_Printf ("still trying...\n");
		CL_UpdateScreen (cl.time);
		start_time = SetNetTime ();
	}

	if (ret == 0) {
		reason = "No Response";
		Con_Printf ("%s\n", reason);
//		strcpy (m_return_reason, reason);
		goto ErrorReturn;
	}

	if (ret == -1) {
		reason = "Network Error";
		Con_Printf ("%s\n", reason);
//		strcpy (m_return_reason, reason);
		goto ErrorReturn;
	}

	ret = MSG_ReadByte (net_message);
	if (ret == CCREP_REJECT) {
		reason = MSG_ReadString (net_message);
		Con_Printf (reason);
//		strncpy (m_return_reason, reason, 31);
		goto ErrorReturn;
	}

	if (ret == CCREP_ACCEPT) {
		memcpy (&sock->addr, &sendaddr, sizeof (struct qsockaddr));

		dfunc.SetSocketPort (&sock->addr, MSG_ReadLong (net_message));
	} else {
		reason = "Bad Response";
		Con_Printf ("%s\n", reason);
//		strcpy (m_return_reason, reason);
		goto ErrorReturn;
	}

	dfunc.GetNameFromAddr (&sendaddr, sock->address);

	Con_Printf ("Connection accepted\n");
	sock->lastMessageTime = SetNetTime ();

	// switch the connection to the specified address
	if (dfunc.Connect (newsock, &sock->addr) == -1) {
		reason = "Connect to Game failed";
		Con_Printf ("%s\n", reason);
//		strcpy (m_return_reason, reason);
		goto ErrorReturn;
	}

	// FIXME: MENUCODE
//	m_return_onerror = false;
	return sock;

  ErrorReturn:
	// FIXME: MENUCODE - do something with reason
	NET_FreeQSocket (sock);
  ErrorReturn2:
	dfunc.CloseSocket (newsock);
	// FIXME: MENUCODE
//	if (m_return_onerror) {
//		key_dest = key_menu;
//		m_state = m_return_state;
//		m_return_onerror = false;
//	}
	return NULL;
}

qsocket_t  *
Datagram_Connect (const char *host)
{
	qsocket_t  *ret = NULL;

	for (net_landriverlevel = 0; net_landriverlevel < net_numlandrivers;
		 net_landriverlevel++)
		if (net_landrivers[net_landriverlevel].initialized)
			if ((ret = _Datagram_Connect (host)) != NULL)
				break;
	return ret;
}