1HEADmaster

14 files changed, 2824 insertions, 0 deletions

diff --git a/networksystem/netchannel.cpp b/networksystem/netchannel.cpp
new file mode 100644
index 0000000..d588d67
--- /dev/null
+++ b/networksystem/netchannel.cpp
@@ -0,0 +1,922 @@
+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+//===========================================================================//
+
+#include "NetChannel.h"
+#include "UDP_Socket.h"
+#include "tier1/utlbuffer.h"
+#include "networksystem/inetworkmessage.h"
+#include "networksystem.h"
+
+// memdbgon must be the last include file in a .cpp file!!!
+#include "tier0/memdbgon.h"
+
+
+//-----------------------------------------------------------------------------
+// Construction/Destruction
+//-----------------------------------------------------------------------------
+CNetChannel::CNetChannel()
+{
+	m_pSocket = NULL; // invalid
+	remote_address.Clear();
+	last_received = 0;
+	connect_time = 0;
+	m_ConnectionState = CONNECTION_STATE_DISCONNECTED;
+	Q_strncpy( m_Name, "", sizeof(m_Name) ); 
+
+	m_MessageHandler = NULL;
+
+	m_StreamUnreliable.StartWriting(m_UnreliableDataBuffer, sizeof(m_UnreliableDataBuffer));
+	m_StreamUnreliable.SetDebugName( "netchan_t::unreliabledata" );
+
+	m_StreamReliable.StartWriting(m_ReliableDataBuffer, sizeof(m_ReliableDataBuffer));
+	m_StreamReliable.SetDebugName( "netchan_t::reliabledata" );
+
+	m_Rate		= DEFAULT_RATE;
+	m_Timeout	= SIGNON_TIME_OUT;
+
+	m_PacketDrop = 0;
+
+	// Prevent the first message from getting dropped after connection is set up.
+
+	m_nOutSequenceNr = 1;	// otherwise it looks like a 	
+	m_nInSequenceNr = 0;
+	m_nOutSequenceNrAck = 0;
+	m_nOutReliableState = 0; // our current reliable state
+	m_nInReliableState = 0;	// last remote reliable state
+
+	// FlowReset();
+}
+
+CNetChannel::~CNetChannel()
+{
+	Shutdown( "NetChannel removed." );
+}
+
+
+//-----------------------------------------------------------------------------
+// called to open a channel to a remote system
+//-----------------------------------------------------------------------------
+void CNetChannel::Setup( bool serverSide, const netadr_t *adr, CUDPSocket *sendSocket, char const *name, INetworkMessageHandler *handler )
+{
+	Assert( name ); 
+	Assert( handler );
+	Assert( adr );
+
+	m_pSocket = sendSocket;
+
+	// remote_address may be NULL for fake channels (demo playback etc)
+	remote_address = *adr;
+	
+	last_received		= g_pNetworkSystemImp->GetTime();
+	connect_time		= last_received;
+	
+	Q_strncpy( m_Name, name, sizeof(m_Name) ); 
+
+	m_MessageHandler = handler;
+
+	m_StreamUnreliable.StartWriting(m_UnreliableDataBuffer, sizeof(m_UnreliableDataBuffer));
+	m_StreamUnreliable.SetDebugName( "netchan_t::unreliabledata" );
+
+	m_ReliableDataBufferMP.EnsureCapacity( NET_MAX_PAYLOAD );
+	m_StreamReliable.StartWriting( m_ReliableDataBufferMP.Base(), NET_MAX_PAYLOAD );
+	m_StreamReliable.SetDebugName( "netchan_t::reliabledata" );
+
+	m_Rate		= DEFAULT_RATE;
+	m_Timeout	= SIGNON_TIME_OUT;
+	m_PacketDrop = 0;
+
+	// Prevent the first message from getting dropped after connection is set up.
+
+	m_nOutSequenceNr = 1;	// otherwise it looks like a 	
+	m_nInSequenceNr = 0;
+	m_nOutSequenceNrAck = 0;
+	m_nOutReliableState = 0; // our current reliable state
+	m_nInReliableState = 0;	// last remote reliable state
+	m_nChokedPackets = 0;
+	m_fClearTime = 0.0;
+	m_ConnectionState = CONNECTION_STATE_CONNECTED;
+
+//	FlowReset();
+
+	// tell message handler to register know netmessages
+	m_MessageHandler->OnConnectionStarted( this );
+}
+
+
+void CNetChannel::Shutdown( const char *pReason )
+{
+	// send discconect
+	if ( !m_pSocket )
+		return;
+
+	Clear(); // free all buffers (reliable & unreliable)
+
+	if ( pReason )
+	{
+		// send disconnect message
+		WriteSystemNetworkMessage( m_StreamUnreliable, net_disconnect );
+		m_StreamUnreliable.WriteString( pReason );
+		Transmit();	// push message out
+	}
+
+	m_pSocket = NULL; // signals that netchannel isn't valid anymore
+
+	remote_address.Clear();
+
+	m_ConnectionState = CONNECTION_STATE_DISCONNECTED;
+	if ( m_MessageHandler )
+	{
+		m_MessageHandler->OnConnectionClosing( this, pReason );
+		m_MessageHandler = NULL;
+	}
+}
+
+
+//-----------------------------------------------------------------------------
+// Channel connection state
+//-----------------------------------------------------------------------------
+ConnectionStatus_t CNetChannel::GetConnectionState( )
+{
+	return m_ConnectionState;
+}
+
+void CNetChannel::SetConnectionState( ConnectionStatus_t state )
+{
+	m_ConnectionState = state;
+}
+
+
+/*
+void CNetChannel::GetSequenceData( int &nOutSequenceNr, int &nInSequenceNr, int &nOutSequenceNrAck )
+{
+	nOutSequenceNr = m_nOutSequenceNr;
+	nInSequenceNr = m_nInSequenceNr;
+	nOutSequenceNrAck = m_nOutSequenceNrAck;
+}
+
+void CNetChannel::SetSequenceData( int nOutSequenceNr, int nInSequenceNr, int nOutSequenceNrAck )
+{
+	Assert( IsPlayback() );
+
+	m_nOutSequenceNr = nOutSequenceNr;
+	m_nInSequenceNr = nInSequenceNr;
+	m_nOutSequenceNrAck = nOutSequenceNrAck;
+}
+*/
+
+void CNetChannel::SetTimeout(float seconds)
+{
+	m_Timeout = seconds;
+
+	if ( m_Timeout > 3600.0f )
+	{
+		m_Timeout = 3600.0f; // 1 hour maximum
+	} 
+	else if ( m_Timeout < CONNECTION_PROBLEM_TIME )
+	{
+		m_Timeout = CONNECTION_PROBLEM_TIME; // allow at least this minimum
+	}
+}
+
+void CNetChannel::SetDataRate(float rate)
+{
+	m_Rate = clamp( rate, (float)MIN_RATE, (float)MAX_RATE );
+}
+
+const char * CNetChannel::GetName() const
+{
+	return m_Name;
+}
+
+const char * CNetChannel::GetAddress() const
+{
+	return remote_address.ToString();
+}
+
+
+/*
+int CNetChannel::GetDropNumber() const
+{
+	return m_PacketDrop;
+}
+*/
+
+/*
+===============
+CNetChannel::CanSendPacket
+
+Returns true if the bandwidth choke isn't active
+================
+*/
+bool CNetChannel::CanSendPacket () const
+{
+	return m_fClearTime < g_pNetworkSystemImp->GetTime();
+}
+
+/*
+void CNetChannel::FlowReset( void )
+{
+	Q_memset( m_DataFlow, 0, sizeof( m_DataFlow ) );
+	Q_memset( m_MsgStats, 0, sizeof( m_MsgStats ) );
+}
+
+void CNetChannel::FlowNewPacket(int flow, int seqnr, int acknr, int nChoked, int nSize )
+{
+	netflow_t * pflow = &m_DataFlow[ flow ];
+	
+	// if frame_number != ( current + 1 ) mark frames between as invalid
+
+	netframe_t *pframe = NULL;
+
+	if ( seqnr > pflow->currentindex )
+	{
+		for ( int i = pflow->currentindex+1; i <= seqnr; i++ )
+		{
+			pframe = &pflow->frames[ i & NET_FRAMES_MASK ];
+
+			pframe->time = GetTime();	// now
+			pframe->valid = false;
+			pframe->size = 0;
+			pframe->latency = -1.0f; // not acknowledged yet
+			pframe->choked = 0; // not acknowledged yet
+			Q_memset( &pframe->msggroups, 0, sizeof(pframe->msggroups) );
+		}
+
+		pframe->choked = nChoked;
+		pframe->size = nSize;
+		pframe->valid = true;
+	}
+	else
+	{
+		Assert( seqnr > pflow->currentindex );
+	}
+
+	pflow->totalpackets++;
+	pflow->currentindex = seqnr;
+	pflow->currentframe = pframe;
+
+	// updated ping for acknowledged packet
+
+	int aflow = (flow==FLOW_OUTGOING) ? FLOW_INCOMING : FLOW_OUTGOING;
+
+	if ( acknr <= (m_DataFlow[aflow].currentindex - NET_FRAMES_BACKUP) )
+		return;	// acknowledged packet isn't in backup buffer anymore
+	
+	netframe_t * aframe = &m_DataFlow[aflow].frames[ acknr  & NET_FRAMES_MASK ];
+
+	if ( aframe->valid && aframe->latency == -1.0f )
+	{
+		// update ping for acknowledged packet, if not already acknowledged before
+		
+		aframe->latency = GetTime() - aframe->time;
+
+		if ( aframe->latency < 0.0f )
+			aframe->latency = 0.0f;
+	}
+}
+
+void CNetChannel::FlowUpdate(int flow, int addbytes)
+{
+	netflow_t * pflow = &m_DataFlow[ flow ];
+	pflow->totalbytes += addbytes;
+
+	if ( pflow->nextcompute > GetTime() )
+		return;
+
+	pflow->nextcompute = GetTime() + FLOW_INTERVAL;
+
+	int		totalvalid = 0;
+	int		totalinvalid = 0;
+	int		totalbytes = 0;
+	float	totallatency = 0.0f;
+	int		totallatencycount = 0;
+	int		totalchoked = 0;
+
+	float   starttime = FLT_MAX;
+	float	endtime = 0.0f;
+
+	netframe_t *pprev = &pflow->frames[ NET_FRAMES_BACKUP-1 ];
+
+	for ( int i = 0; i < NET_FRAMES_BACKUP; i++ )
+	{
+		// Most recent message then backward from there
+		netframe_t * pcurr = &pflow->frames[ i ];
+
+		if ( pcurr->valid )
+		{
+			if ( pcurr->time < starttime )
+				starttime = pcurr->time;
+
+			if ( pcurr->time > endtime )
+				endtime = pcurr->time;
+		
+			totalvalid++;
+			totalchoked += pcurr->choked;
+			totalbytes += pcurr->size;
+
+			if ( pcurr->latency > -1.0f  )
+			{
+				totallatency += pcurr->latency; 
+				totallatencycount++;
+			}
+		}
+		else
+		{
+			totalinvalid++;
+		}
+		
+		pprev = pcurr;
+	}
+
+	float totaltime = endtime - starttime;
+
+	if ( totaltime > 0.0f )
+	{
+		pflow->avgbytespersec *= FLOW_AVG;
+		pflow->avgbytespersec += ( 1.0f - FLOW_AVG ) * ((float)totalbytes / totaltime);
+
+		pflow->avgpacketspersec *= FLOW_AVG;
+		pflow->avgpacketspersec += ( 1.0f - FLOW_AVG ) * ((float)totalvalid / totaltime);
+	}
+
+	int totalPackets = totalvalid + totalinvalid;
+			
+	if ( totalPackets > 0 )
+	{
+		pflow->avgloss *= FLOW_AVG;
+		pflow->avgloss += ( 1.0f - FLOW_AVG ) * ((float)(totalinvalid-totalchoked)/totalPackets);
+
+		if ( pflow->avgloss < 0 )
+			pflow->avgloss = 0;
+		
+		pflow->avgchoke *= FLOW_AVG;
+		pflow->avgchoke += ( 1.0f - FLOW_AVG ) * ((float)totalchoked/totalPackets);
+	}
+	
+	if ( totallatencycount>0 )
+	{
+		float newping = totallatency / totallatencycount ;
+		pflow->latency = newping;
+		pflow->avglatency*= FLOW_AVG;
+		pflow->avglatency += ( 1.0f - FLOW_AVG ) * newping;
+	}
+}
+*/
+
+void CNetChannel::SetChoked( void )
+{
+	m_nOutSequenceNr++;	// sends to be done since move command use sequence number
+	m_nChokedPackets++;
+}
+
+bool CNetChannel::Transmit( bool onlyReliable /* =false */ )
+{
+	if ( onlyReliable )
+	{
+		m_StreamUnreliable.Reset();
+	}
+
+	return ( SendDatagram( NULL ) != 0 );
+}
+
+/*
+===============
+CNetChannel::TransmitBits
+
+tries to send an unreliable message to a connection, and handles the
+transmition / retransmition of the reliable messages.
+
+A 0 length will still generate a packet and deal with the reliable messages.
+================
+*/
+int CNetChannel::SendDatagram( bf_write *datagram )
+{
+	byte		send_buf[ NET_MAX_MESSAGE ];
+		
+	// first increase out sequence number
+	
+	// check, if fake client, then fake send also
+	if ( remote_address.GetType() == NA_NULL )	
+	{
+		// this is a demo channel, fake sending all data
+		m_fClearTime = 0.0;		// no bandwidth delay
+		m_nChokedPackets = 0;	// Reset choke state
+		m_StreamReliable.Reset();		// clear current reliable buffer
+		m_StreamUnreliable.Reset();		// clear current unrelaible buffer
+		m_nOutSequenceNr++;
+		return m_nOutSequenceNr-1;
+	}
+
+	// process all new and pending reliable data, return true if reliable data should
+	// been send with this packet
+
+	if ( m_StreamReliable.IsOverflowed() )
+	{
+		Msg ("%s:send reliable stream overflow\n" ,remote_address.ToString());
+		return 0;
+	}
+
+	bf_write send( "CNetChannel_TransmitBits->send", send_buf, sizeof(send_buf) );
+
+	// Prepare the packet header
+	// build packet flags
+	unsigned char flags = 0;
+
+	// start writing packet
+	send.WriteLong ( m_nOutSequenceNr );
+	send.WriteLong ( m_nInSequenceNr );
+
+	bf_write flagsPos = send; // remember flags byte position
+
+	send.WriteByte ( 0 ); // write correct flags value later
+	send.WriteByte ( m_nInReliableState );
+
+	if ( m_nChokedPackets > 0 )
+	{
+		flags |= PACKET_FLAG_CHOKED;
+		send.WriteByte ( m_nChokedPackets & 0xFF );	// send number of choked packets
+	}
+
+	/*
+	if ( SendSubChannelData( send ) )
+	{
+		flags |= PACKET_FLAG_RELIABLE;
+	}
+	*/
+
+	// Is there room for given datagram data. the datagram data 
+	// is somewhat more important than the normal unreliable data
+	// this is done to allow some kind of snapshot behaviour
+	// weather all data in datagram is transmitted or none.
+	if ( datagram )
+	{
+		if( datagram->GetNumBitsWritten() < send.GetNumBitsLeft() )
+		{
+			send.WriteBits( datagram->GetData(), datagram->GetNumBitsWritten() );
+		}
+		else
+		{
+			DevMsg("CNetChannel::SendDatagram:  data would overfow, ignoring\n");
+		}
+	}
+
+	// Is there room for the unreliable payload?
+	if ( m_StreamUnreliable.GetNumBitsWritten() < send.GetNumBitsLeft() )
+	{
+		send.WriteBits(m_StreamUnreliable.GetData(), m_StreamUnreliable.GetNumBitsWritten() );
+	}
+	else
+	{
+		DevMsg("CNetChannel::SendDatagram:  Unreliable would overfow, ignoring\n");
+	}
+
+	m_StreamUnreliable.Reset();	// clear unreliable data buffer
+
+	// Deal with packets that are too small for some networks
+	while ( send.GetNumBytesWritten() < MIN_ROUTEABLE_PACKET )		
+	{
+		// Go ahead and pad some bits as long as needed
+		WriteSystemNetworkMessage( send, net_nop );
+	}
+
+	// fill last bits in last byte with NOP if necessary
+	int nRemainingBits = send.GetNumBitsWritten() % 8;
+	int nHeaderSize = g_pNetworkSystemImp->GetGroupBitCount() + g_pNetworkSystemImp->GetTypeBitCount();
+	while ( nRemainingBits > 0 && nRemainingBits <= ( 8 - nHeaderSize ) )
+	{
+		WriteSystemNetworkMessage( send, net_nop );
+		nRemainingBits += nHeaderSize;
+	}
+
+	flagsPos.WriteByte( flags ); // write correct flags value
+
+	// Send the datagram
+	m_pSocket->SendTo( remote_address, send.GetData(), send.GetNumBytesWritten() );
+
+	// update stats
+
+	int nTotalSize = send.GetNumBytesWritten() + UDP_HEADER_SIZE;
+
+//	FlowNewPacket( FLOW_OUTGOING, m_nOutSequenceNr, m_nInSequenceNr, m_nChokedPackets, nTotalSize );
+//	FlowUpdate( FLOW_OUTGOING, nTotalSize );
+	
+	float flTime = g_pNetworkSystemImp->GetTime();
+	if ( m_fClearTime < flTime )
+	{
+		m_fClearTime = flTime;
+	}
+
+	// calc cleantime when channel will be ready for next packet
+	Assert( m_Rate != 0.0f );
+	m_fClearTime += (float)( nTotalSize ) / (float) m_Rate;
+	
+	m_nChokedPackets = 0;
+	m_nOutSequenceNr++;
+
+	return m_nOutSequenceNr-1; // return send seq nr
+}
+
+bool CNetChannel::ProcessControlMessage( int cmd, bf_read &buf )
+{
+	switch( cmd )
+	{
+	case net_nop:
+		return true;
+
+	case net_disconnect:
+		{
+			char pReason[1024];
+			buf.ReadString( pReason, sizeof(pReason) );
+			Shutdown( pReason );
+		}
+		return false;
+
+	default:
+		Msg( "CNetChannel: received bad control cmd %i from %s.\n", cmd, remote_address.ToString() );
+		return false;
+	}	
+}
+
+bool CNetChannel::ProcessMessages( bf_read &buf )
+{
+	//int startbit = buf.GetNumBitsRead();
+	int nGroupCount = g_pNetworkSystemImp->GetGroupBitCount();
+	int nTypeCount = g_pNetworkSystemImp->GetTypeBitCount();
+
+	while ( true )
+	{
+		if ( buf.IsOverflowed() )
+			return false;
+
+		// Are we at the end?
+		if ( buf.GetNumBitsLeft() < ( nGroupCount + nTypeCount ) )
+			break;
+
+		unsigned int group = buf.ReadUBitLong( nGroupCount );
+		unsigned int type = buf.ReadUBitLong( nTypeCount );
+
+		if ( group == net_group_networksystem )
+		{
+			if ( !ProcessControlMessage( type, buf ) )
+				return g_pNetworkSystemImp->IsNetworkEventCreated(); // disconnect or error
+			continue;
+		}
+
+		// see if we have a registered message object for this type
+		INetworkMessage	*pNetMessage = g_pNetworkSystemImp->FindNetworkMessage( group, type );
+		if ( !pNetMessage )
+		{
+			Msg( "Netchannel: unknown net message (%i:%i) from %s.\n", group, type, remote_address.ToString() );
+			Assert ( 0 );
+			return false;
+		}
+
+		// Attach it to the correct netchannel
+		pNetMessage->SetNetChannel( this );
+
+		// let message parse itself from buffe
+		const char *pGroupName = pNetMessage->GetGroupName();
+		const char *pMessageName = pNetMessage->GetName();
+		
+		//int startbit = buf.GetNumBitsRead();
+
+		if ( !pNetMessage->ReadFromBuffer( buf ) )
+		{
+			Msg( "Netchannel: failed reading message %s [%s] from %s.\n", pMessageName, pGroupName, remote_address.ToString() );
+			Assert ( 0 );
+			return false;
+		}
+
+		// UpdateMessageStats( netmsg->GetGroup(), buf.GetNumBitsRead() - startbit );
+
+		// Create a network event
+		NetworkMessageReceivedEvent_t *pReceived = g_pNetworkSystemImp->CreateNetworkEvent< NetworkMessageReceivedEvent_t >( );
+		pReceived->m_nType = NETWORK_EVENT_MESSAGE_RECEIVED;
+		pReceived->m_pChannel = this;
+		pReceived->m_pNetworkMessage = pNetMessage;
+		return true; // ok fine
+	}
+
+	return false; // ok fine, but don't keep processing this packet
+}
+
+int CNetChannel::ProcessPacketHeader( bf_read& message )
+{
+	// get sequence numbers		
+	int sequence	= message.ReadLong();
+	int sequence_ack= message.ReadLong();
+	int flags		= message.ReadByte();
+	int relState	= message.ReadByte();	// reliable state of 8 subchannels
+	int nChoked		= 0;	// read later if choked flag is set
+	//int i,j;
+
+	NOTE_UNUSED( relState );
+
+	if ( flags & PACKET_FLAG_CHOKED )
+		nChoked = message.ReadByte(); 
+
+// discard stale or duplicated packets
+	if (sequence <= m_nInSequenceNr )
+	{
+		/*
+		if ( net_showdrop.GetInt() )
+		{
+			if ( sequence == m_nInSequenceNr )
+			{
+				Msg ("%s:duplicate packet %i at %i\n"
+					, remote_address.ToString ()
+					, sequence
+					, m_nInSequenceNr);
+			}
+			else
+			{
+				Msg ("%s:out of order packet %i at %i\n"
+					, remote_address.ToString ()
+					, sequence
+					, m_nInSequenceNr);
+			}
+		}
+		*/
+		
+		return -1;
+	}
+
+//
+// dropped packets don't keep the message from being used
+//
+	m_PacketDrop = sequence - (m_nInSequenceNr + nChoked + 1);
+
+	if ( m_PacketDrop > 0 )
+	{
+		/*
+		if ( net_showdrop.GetInt() )
+		{
+			Msg ("%s:Dropped %i packets at %i\n"
+			,remote_address.ToString(), m_PacketDrop, sequence );
+		}
+		*/
+	}
+
+	m_nInSequenceNr = sequence;
+	m_nOutSequenceNrAck = sequence_ack;
+
+	// Update data flow stats
+	// FlowNewPacket( FLOW_INCOMING, m_nInSequenceNr, m_nOutSequenceNrAck, nChoked, packet->size + UDP_HEADER_SIZE );
+
+	return flags;
+}
+
+
+//-----------------------------------------------------------------------------
+// CNetChannel::ProcessPacket
+//
+// called when a new packet has arrived for this netchannel
+// sequence numbers are extracted, fragments/file streams stripped 
+// and then the netmessages processed
+//-----------------------------------------------------------------------------
+bool CNetChannel::StartProcessingPacket( CNetPacket *packet )
+{
+	if ( !m_MessageHandler )
+		return false;
+
+	netadr_t from = packet->m_From;
+	if ( remote_address.IsValid() && !from.CompareAdr ( remote_address ) )
+		return false;
+
+	// Update data flow stats
+	//FlowUpdate( FLOW_INCOMING, msg.TellPut() + UDP_HEADER_SIZE );
+
+	int flags = ProcessPacketHeader( packet->m_Message );
+	if ( flags == -1 )
+		return false; // invalid header/packet
+
+	/*
+	if ( net_showudp.GetInt() && net_showudp.GetInt() != 3 )
+	{
+		Msg ("UDP <- %s: sz=%i seq=%i ack=%i rel=%i tm=%f\n"
+			, GetName()
+			, packet->m_nSizeInBytes
+			, m_nInSequenceNr & 63
+			, m_nOutSequenceNrAck & 63 
+			, flags & PACKET_FLAG_RELIABLE	 ? 1 : 0
+			, GetTime() );
+	}
+	*/
+
+	last_received = g_pNetworkSystemImp->GetTime();
+
+	// tell message handler that a new packet has arrived
+	m_MessageHandler->OnPacketStarted( m_nInSequenceNr, m_nOutSequenceNrAck );
+
+	if ( flags & PACKET_FLAG_RELIABLE )
+	{
+		/*
+		int i, bit = 1<<msg.ReadUBitLong( 3 );
+
+		for ( i=0; i<MAX_STREAMS; i++ )
+		{
+			if ( msg.ReadOneBit() != 0 )
+			{
+				if ( !ReadSubChannelData( msg, i ) )
+					return false; // error while reading fragments, drop whole packet
+			}
+		}
+
+		// flip subChannel bit to signal successfull receiving
+		FLIPBIT(m_nInReliableState, bit);
+		
+		for ( i=0; i<MAX_STREAMS; i++ )
+		{
+			if ( !CheckReceivingList( i ) )
+				return false; // error while processing 
+		}
+		*/
+	}
+
+	return true;
+}
+
+bool CNetChannel::ProcessPacket( CNetPacket *packet )
+{
+	return ProcessMessages( packet->m_Message );
+}
+
+void CNetChannel::EndProcessingPacket( CNetPacket *packet )
+{
+	// tell message handler that packet is completely parsed
+	if ( m_MessageHandler	)
+	{
+		m_MessageHandler->OnPacketFinished();
+	}
+}
+
+bool CNetChannel::AddNetMsg( INetworkMessage *msg, bool bForceReliable )
+{
+	if ( msg->IsReliable() || bForceReliable )
+	{
+		WriteNetworkMessage( m_StreamReliable, msg );
+		if ( m_StreamReliable.IsOverflowed() )
+			return false;
+		return msg->WriteToBuffer( m_StreamReliable );
+	}
+
+	WriteNetworkMessage( m_StreamUnreliable, msg );
+	if ( m_StreamUnreliable.IsOverflowed() )
+		return false;
+	return msg->WriteToBuffer( m_StreamUnreliable );
+}
+
+bool CNetChannel::AddData( bf_write &msg, bool bReliable )
+{
+	// Always queue any pending reliable data ahead of the fragmentation buffer
+
+	if ( msg.GetNumBitsWritten() <= 0 )
+		return true;
+
+	bf_write * buf = bReliable ? &m_StreamReliable : &m_StreamUnreliable;
+
+
+	if ( msg.GetNumBitsWritten() > buf->GetNumBitsLeft() )
+	{
+		if (  bReliable )
+		{
+			Msg( "ERROR! SendData reliabe data too big (%i)", msg.GetNumBytesWritten() );
+		}
+
+		return false;
+	}
+
+	return buf->WriteBits( msg.GetData(), msg.GetNumBitsWritten() );
+}
+
+int CNetChannel::GetDataRate() const
+{
+	return m_Rate;
+}
+
+bool CNetChannel::HasPendingReliableData( void )
+{
+	return ( m_StreamReliable.GetNumBitsWritten() > 0 );
+}
+
+float CNetChannel::GetTimeConnected() const
+{
+	float t = g_pNetworkSystemImp->GetTime() - connect_time;
+	return (t>0.0f) ? t : 0.0f ;
+}
+
+const netadr_t & CNetChannel::GetRemoteAddress() const
+{
+	return remote_address;
+}
+
+bool CNetChannel::IsTimedOut() const
+{
+	if ( m_Timeout == -1.0f )
+		return false;
+	else
+		return ( last_received + m_Timeout ) < g_pNetworkSystemImp->GetTime();
+}
+
+bool CNetChannel::IsTimingOut() const
+{
+	if ( m_Timeout == -1.0f )
+		return false;
+	else
+		return (last_received + CONNECTION_PROBLEM_TIME) < g_pNetworkSystemImp->GetTime();
+}
+
+float CNetChannel::GetTimeSinceLastReceived() const
+{
+	float t = g_pNetworkSystemImp->GetTime() - last_received;
+	return (t>0.0f) ? t : 0.0f ;
+}
+
+bool CNetChannel::IsOverflowed() const
+{
+	return m_StreamReliable.IsOverflowed();
+}
+
+void CNetChannel::Clear()
+{
+	Reset();
+}
+
+void CNetChannel::Reset()
+{
+	// FlowReset();
+	m_StreamUnreliable.Reset();  // clear any pending unreliable data messages
+	m_StreamReliable.Reset();	 // clear any pending reliable data messages
+	m_fClearTime = 0.0;			 // ready to send
+	m_nChokedPackets = 0;
+}
+
+CUDPSocket *CNetChannel::GetSocket()
+{
+	return m_pSocket;
+}
+
+float CNetChannel::GetAvgData( int flow ) const
+{
+	return 0.0f;
+//	return m_DataFlow[flow].avgbytespersec;
+}
+
+float CNetChannel::GetAvgPackets( int flow ) const
+{
+	return 0.0f;
+//	return m_DataFlow[flow].avgpacketspersec;
+}
+
+//-----------------------------------------------------------------------------
+// Purpose: 
+// Input  : *chan - 
+//-----------------------------------------------------------------------------
+int CNetChannel::GetTotalData(int flow ) const
+{
+	return 0;
+//	return m_DataFlow[flow].totalbytes;
+}
+
+/*
+int	CNetChannel::GetSequenceNr( int flow ) const
+{
+	if ( flow == FLOW_OUTGOING )
+	{
+		return m_nOutSequenceNr;
+	}
+	else if ( flow == FLOW_INCOMING )
+	{
+		return m_nInSequenceNr;
+	}
+	
+	return 0;
+}
+*/
+
+float CNetChannel::GetLatency( int flow ) const
+{
+	return 0.0f;
+//	return m_DataFlow[flow].latency;
+}
+
+float CNetChannel::GetAvgChoke( int flow ) const
+{
+	return 0.0f;
+	//return m_DataFlow[flow].avgchoke;
+}
+
+float CNetChannel::GetAvgLatency( int flow ) const
+{
+	return 0.0f;
+	//return m_DataFlow[flow].avglatency;	
+}
+
+float CNetChannel::GetAvgLoss( int flow ) const
+{
+	return 0.0f;
+	//return m_DataFlow[flow].avgloss;
+}
diff --git a/networksystem/netchannel.h b/networksystem/netchannel.h
new file mode 100644
index 0000000..e1a831f
--- /dev/null
+++ b/networksystem/netchannel.h
@@ -0,0 +1,274 @@
+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+//=============================================================================
+
+// Should move to common/networksystem
+
+#ifndef NETCHANNEL_H
+#define NETCHANNEL_H
+#ifdef _WIN32
+#pragma once
+#endif
+
+#include "tier1/bitbuf.h"
+#include "tier1/netadr.h"
+#include "sm_Protocol.h"
+#include "tier1/utlvector.h"
+#include "networksystem/inetworksystem.h"
+#include "tier1/mempool.h"
+
+
+//-----------------------------------------------------------------------------
+// Forward declarations
+//-----------------------------------------------------------------------------
+class CUDPSocket;
+class CUtlBuffer;
+class CNetPacket;
+class CNetChannel;
+class INetChannel;
+
+// 0 == regular, 1 == file stream
+enum
+{
+	FRAG_NORMAL_STREAM = 0,
+	FRAG_FILE_STREAM,
+
+	MAX_STREAMS
+};
+
+#define NET_MAX_DATAGRAM_PAYLOAD 1400
+#define NET_MAX_PAYLOAD_BITS	11		// 2^NET_MAX_PALYLOAD_BITS > NET_MAX_PAYLOAD
+#define DEFAULT_RATE 10000
+#define SIGNON_TIME_OUT	120.0f
+#define CONNECTION_PROBLEM_TIME	15.0f
+
+#define MAX_RATE 50000
+#define MIN_RATE 100
+
+#define FRAGMENT_BITS		8
+#define FRAGMENT_SIZE		(1<<FRAGMENT_BITS)
+#define MAX_FILE_SIZE_BITS	26
+#define MAX_FILE_SIZE		((1<<MAX_FILE_SIZE_BITS)-1)	// maximum transferable size is	64MB
+
+#define NET_MAX_PAYLOAD			4000
+#define NET_MAX_MESSAGE			4096
+#define MIN_ROUTEABLE_PACKET	16
+#define MAX_ROUTEABLE_PACKET	1400	// Ethernet 1518 - ( CRC + IP + UDP header)
+#define UDP_HEADER_SIZE			28
+
+// each channel packet has 1 byte of FLAG bits
+#define PACKET_FLAG_RELIABLE			(1<<0)	// packet contains subchannel stream data
+#define PACKET_FLAG_CHOKED				(1<<1)  // packet was choked by sender
+
+
+// shared commands used by all streams, handled by stream layer, TODO
+
+abstract_class INetworkMessageHandler
+{
+public:
+	virtual void	OnConnectionClosing( INetChannel *channel, char const *reason ) = 0;
+	virtual void	OnConnectionStarted( INetChannel *channel ) = 0;
+
+	virtual void	OnPacketStarted( int inseq, int outseq ) = 0;
+	virtual void	OnPacketFinished() = 0;
+
+protected:
+	virtual ~INetworkMessageHandler() {}
+};
+
+
+
+class INetChannelHandler
+{
+public:
+	virtual	~INetChannelHandler( void ) {};
+
+	virtual void ConnectionStart(INetChannel *chan) = 0;	// called first time network channel is established
+
+	virtual void ConnectionClosing(const char *reason) = 0; // network channel is being closed by remote site
+
+	virtual void ConnectionCrashed(const char *reason) = 0; // network error occured
+
+	virtual void PacketStart(int incoming_sequence, int outgoing_acknowledged) = 0;	// called each time a new packet arrived
+
+	virtual void PacketEnd( void ) = 0; // all messages has been parsed
+
+	virtual void FileRequested(const char *fileName, unsigned int transferID) = 0; // other side request a file for download
+
+	virtual void FileReceived(const char *fileName, unsigned int transferID) = 0; // we received a file
+	
+	virtual void FileDenied(const char *fileName, unsigned int transferID) = 0;	// a file request was denied by other side
+};
+
+
+// server to client
+class CNetPacket
+{
+	DECLARE_FIXEDSIZE_ALLOCATOR( CNetPacket );
+
+public:
+	CNetPacket();
+	~CNetPacket();
+
+	void AddRef();
+	void Release();
+
+public:
+	netadr_t		m_From;				// sender IP
+	CUDPSocket		*m_pSource;			// received source 
+	float			m_flReceivedTime;	// received time
+	unsigned char	*m_pData;			// pointer to raw packet data
+	bf_read			m_Message;			// easy bitbuf data access
+	int				m_nSizeInBytes;		// size in bytes
+
+private:
+	int				m_nRefCount;// Reference count
+};
+
+
+abstract_class IConnectionlessPacketHandler
+{
+public:
+	virtual bool ProcessConnectionlessPacket( CNetPacket *packet ) = 0;	// process a connectionless packet
+
+protected:
+	virtual	~IConnectionlessPacketHandler( void ) {};
+};
+
+abstract_class ILookupChannel
+{
+public:
+
+	virtual INetChannel *FindNetChannel( const netadr_t& from ) = 0;
+};
+
+// FIXME: Make an INetChannel
+class CNetChannel : public INetChannel
+{
+public:
+	explicit CNetChannel();
+	~CNetChannel();
+
+	// Methods of INetChannel
+ 	virtual ConnectionStatus_t GetConnectionState( );
+	virtual const netadr_t &GetRemoteAddress( void ) const;
+
+	void		Setup( bool serverSide, const netadr_t *remote_address, CUDPSocket *sendSocket, char const *name, INetworkMessageHandler *handler );
+	void		Reset();
+	void		Clear();
+	void		Shutdown( const char *reason );
+
+	CUDPSocket *GetSocket();
+
+	void		SetDataRate( float rate );
+	void		SetTimeout( float seconds );
+
+	bool		StartProcessingPacket( CNetPacket *packet );
+	bool		ProcessPacket( CNetPacket *packet );
+	void		EndProcessingPacket( CNetPacket *packet );
+
+	bool		CanSendPacket( void ) const;
+	void		SetChoked( void ); // choke a packet
+	bool		HasPendingReliableData( void );
+
+	// Queues data for sending:
+
+	// send a net message
+	bool		AddNetMsg( INetworkMessage *msg, bool bForceReliable = false );
+
+	// send a chunk of data
+	bool		AddData( bf_write &msg, bool bReliable = true ); 
+
+	// Puts data onto the wire:
+
+	int			SendDatagram( bf_write *data ); // Adds data to unreliable payload and then calls transmits the data
+	bool		Transmit( bool onlyReliable = false ); // send data from buffers (calls SendDataGram( NULL ) )
+
+	bool		IsOverflowed( void ) const;
+	bool		IsTimedOut( void ) const;
+	bool		IsTimingOut() const;
+
+// Info:
+
+	const char  *GetName( void ) const;
+	const char  *GetAddress( void ) const;
+	float		GetTimeConnected( void ) const;
+	float		GetTimeSinceLastReceived( void ) const;
+	int			GetDataRate( void ) const;
+
+	float		GetLatency( int flow ) const;
+	float		GetAvgLatency( int flow ) const;
+	float		GetAvgLoss( int flow ) const;
+	float		GetAvgData( int flow ) const;
+	float		GetAvgChoke( int flow ) const;
+	float		GetAvgPackets( int flow ) const;
+	int			GetTotalData( int flow ) const;
+
+ 	void SetConnectionState( ConnectionStatus_t state );
+
+private:
+	int			ProcessPacketHeader( bf_read &buf );
+	bool		ProcessControlMessage( int cmd, bf_read &buf );
+	bool		ProcessMessages( bf_read &buf );
+
+	ConnectionStatus_t m_ConnectionState;
+
+// last send outgoing sequence number
+	int			m_nOutSequenceNr;
+	// last received incoming sequnec number
+	int			m_nInSequenceNr;
+	// last received acknowledge outgoing sequnce number
+	int			m_nOutSequenceNrAck;
+	
+	// state of outgoing reliable data (0/1) flip flop used for loss detection
+	int			m_nOutReliableState;
+	// state of incoming reliable data
+	int			m_nInReliableState;
+
+	int			m_nChokedPackets;	//number of choked packets
+	int			m_PacketDrop;
+
+// Reliable data buffer, send wich each packet (or put in waiting list)
+	bf_write	m_StreamReliable;
+	byte		m_ReliableDataBuffer[8 * 1024];	// In SP, we don't need much reliable buffer, so save the memory (this is mostly for xbox).
+	CUtlVector<byte> m_ReliableDataBufferMP;
+
+	// unreliable message buffer, cleared wich each packet
+	bf_write	m_StreamUnreliable;
+	byte		m_UnreliableDataBuffer[NET_MAX_DATAGRAM_PAYLOAD];
+
+// don't use any vars below this (only in net_ws.cpp)
+
+	CUDPSocket	*m_pSocket;   // NS_SERVER or NS_CLIENT index, depending on channel.
+	int			m_StreamSocket;	// TCP socket handle
+
+	unsigned int m_MaxReliablePayloadSize;	// max size of reliable payload in a single packet	
+
+	// Address this channel is talking to.
+	netadr_t	remote_address;  
+	
+	// For timeouts.  Time last message was received.
+	float		last_received;		
+	// Time when channel was connected.
+	float      connect_time;       
+
+	// Bandwidth choke
+	// Bytes per second
+	int			m_Rate;				
+	// If realtime > cleartime, free to send next packet
+	float		m_fClearTime;
+
+	float		m_Timeout;		// in seconds 
+
+	char			m_Name[32];		// channel name
+
+// packet history
+	// netflow_t		m_DataFlow[ MAX_FLOWS ];  
+
+	INetworkMessageHandler			*m_MessageHandler;	// who registers and processes messages
+};
+
+
+#endif // NETCHANNEL_H
\ No newline at end of file
diff --git a/networksystem/networkclient.cpp b/networksystem/networkclient.cpp
new file mode 100644
index 0000000..fdd8b04
--- /dev/null
+++ b/networksystem/networkclient.cpp
@@ -0,0 +1,178 @@
+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+//===========================================================================//
+
+#include "networkclient.h"
+#include "UDP_Socket.h"
+#include "NetChannel.h"
+#include "UDP_Process.h"
+#include <winsock.h>
+#include "tier1/bitbuf.h"
+#include "networksystem.h"
+#include "sm_protocol.h"
+
+
+//-----------------------------------------------------------------------------
+// Construction/Destruction
+//-----------------------------------------------------------------------------
+CNetworkClient::CNetworkClient() : m_bConnected( false )
+{
+	m_pSocket = new CUDPSocket;
+}
+
+CNetworkClient::~CNetworkClient()
+{
+	delete m_pSocket;
+}
+
+
+//-----------------------------------------------------------------------------
+// Init/Shutdown
+//-----------------------------------------------------------------------------
+bool CNetworkClient::Init( int nListenPort )
+{
+	if ( !m_pSocket->Init( nListenPort ) )
+	{
+		Warning( "CNetworkClient:  Unable to create socket!!!\n" );
+		return false;
+	}
+	return true;
+}
+
+void CNetworkClient::Shutdown()
+{
+	m_pSocket->Shutdown();
+}
+
+#define SPEW_MESSAGES 
+
+#if defined( SPEW_MESSAGES )
+#define SM_SPEW_MESSAGE( code, remote ) \
+	Warning( "Message:  %s from '%s'\n", #code, remote );
+#else
+#define SM_SPEW_MESSAGE( code, remote ) 
+#endif
+
+// process a connectionless packet
+bool CNetworkClient::ProcessConnectionlessPacket( CNetPacket *packet )
+{
+	int code = packet->m_Message.ReadByte();
+	switch ( code )
+	{
+	case s2c_connect_accept:
+		{
+			SM_SPEW_MESSAGE( s2c_connect_accept, packet->m_From.ToString() );
+
+			m_NetChan.Setup( false, &packet->m_From, m_pSocket, "client", this );
+			m_bConnected = true;
+		}
+		break;
+	default:
+		{
+			Warning( "CSmServer::ProcessConnectionlessPacket:  Unknown code '%i' from '%s'\n",
+				code, packet->m_From.ToString() );
+		}
+		break;
+	}
+
+	return true;
+}
+
+INetChannel *CNetworkClient::FindNetChannel( const netadr_t& from )
+{
+	if ( from.CompareAdr( m_NetChan.GetRemoteAddress() ) )
+		return &m_NetChan;
+	return NULL;
+}
+
+void CNetworkClient::ReadPackets( void )
+{
+	UDP_ProcessSocket( m_pSocket, this, this );	
+}
+
+void CNetworkClient::SendUpdate()
+{
+	if ( m_bConnected )
+	{
+		m_NetChan.SendDatagram( NULL );
+	}
+}
+
+
+void CNetworkClient::Disconnect()
+{
+	if ( !m_bConnected )
+		return;
+
+	byte data[ 512 ];
+	bf_write buf( "CNetworkClient::Connect", data, sizeof( data ) );
+
+	WriteSystemNetworkMessage( buf, net_disconnect );
+	buf.WriteString( "client disconnected" );
+
+	m_NetChan.SendDatagram( &buf );
+	m_NetChan.SendDatagram( &buf );
+	m_NetChan.SendDatagram( &buf );
+}
+
+bool CNetworkClient::Connect( char const *server, int port /*=SM_SERVER_PORT*/ )
+{
+	byte data[ 512 ];
+	bf_write buf( "CNetworkClient::Connect", data, sizeof( data ) );
+
+	buf.WriteLong( -1 );
+	buf.WriteByte( c2s_connect );
+
+	netadr_t remote;
+	remote.type = NA_IP;
+	remote.port = htons( (unsigned short)port );
+	
+	// Resolve remote name
+	sockaddr sa;
+	if ( !Q_stricmp( server, "localhost" ) )
+	{
+		remote.ip[ 0 ] = 127;
+		remote.ip[ 1 ] = 0;
+		remote.ip[ 2 ] = 0;
+		remote.ip[ 3 ] = 1;
+	}
+	else
+	{
+		if ( !g_pNetworkSystemImp->StringToSockaddr( server, &sa ) )
+		{
+			Msg( "Unable to resolve '%s'\n", server );
+			return false;
+		}
+
+		remote.SetFromSockadr( &sa );
+	}
+
+	m_NetChan.SetConnectionState( CONNECTION_STATE_CONNECTING );
+
+	return m_pSocket->SendTo( remote, buf.GetData(), buf.GetNumBytesWritten() );
+}
+
+void CNetworkClient::OnConnectionClosing( INetChannel *channel, char const *reason )
+{
+	Warning( "OnConnectionClosing '%s'\n", reason );
+	if ( channel == &m_NetChan )
+	{
+		m_NetChan.Shutdown( "received disconnect\n" );
+		m_bConnected = false;
+	}
+}
+
+void CNetworkClient::OnConnectionStarted( INetChannel *channel )
+{
+	Warning( "OnConnectionStarted\n" );
+}
+
+void CNetworkClient::OnPacketStarted( int inseq, int outseq )
+{
+}
+
+void CNetworkClient::OnPacketFinished()
+{
+}
\ No newline at end of file
diff --git a/networksystem/networkclient.h b/networksystem/networkclient.h
new file mode 100644
index 0000000..40f3467
--- /dev/null
+++ b/networksystem/networkclient.h
@@ -0,0 +1,54 @@
+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+//===========================================================================//
+
+#ifndef CLIENT_H
+#define CLIENT_H
+#ifdef _WIN32
+#pragma once
+#endif
+
+#include "NetChannel.h"
+
+class CNetworkClient : public IConnectionlessPacketHandler, public INetworkMessageHandler, public ILookupChannel
+{
+public:
+	CNetworkClient();
+	virtual ~CNetworkClient();
+
+	bool	Init( int nListenPort );
+	void	Shutdown();
+
+	bool	Connect( const char *server, int port );
+	void	Disconnect();
+
+	// IConnectionlessPacketHandler
+	virtual bool ProcessConnectionlessPacket( CNetPacket *packet );	// process a connectionless packet
+
+	// INetworkMessageHandler
+	virtual void	OnConnectionClosing( INetChannel *channel, char const *reason );
+	virtual void	OnConnectionStarted( INetChannel *channel );
+
+	virtual void	OnPacketStarted( int inseq, int outseq );
+	virtual void	OnPacketFinished();
+
+	// ILookupChannel
+    virtual INetChannel *FindNetChannel( const netadr_t& from ) ;
+
+	INetChannel *GetNetChannel()
+	{
+		return &m_NetChan;
+	}
+
+	void ReadPackets();
+	void SendUpdate();
+
+	CUDPSocket *m_pSocket;
+	
+	CNetChannel		m_NetChan;
+	bool			m_bConnected;
+};
+
+#endif // CLIENT_H
diff --git a/networksystem/networkserver.cpp b/networksystem/networkserver.cpp
new file mode 100644
index 0000000..9951e6c
--- /dev/null
+++ b/networksystem/networkserver.cpp
@@ -0,0 +1,224 @@
+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+//===========================================================================//
+
+#include "networkserver.h"
+#include "networksystem.h"
+#include "icvar.h"
+#include "filesystem.h"
+#include "UDP_Socket.h"
+#include "sm_protocol.h"
+#include "NetChannel.h"
+#include "UDP_Process.h"
+#include <winsock.h>
+#include "networkclient.h"
+
+
+
+//-----------------------------------------------------------------------------
+//
+// Implementation of CPlayer
+//
+//-----------------------------------------------------------------------------
+CNetworkServer::CNetworkServer( )
+{
+	m_pSocket = new CUDPSocket;
+}
+
+CNetworkServer::~CNetworkServer()
+{
+	delete m_pSocket;
+}
+
+bool CNetworkServer::Init( int nServerPort )
+{
+	if ( !m_pSocket->Init( nServerPort ) )
+	{
+		Warning( "CNetworkServer:  Unable to create socket!!!\n" );
+		return false;
+	}
+
+	return true;
+}
+
+void CNetworkServer::Shutdown()
+{
+	m_pSocket->Shutdown();
+}
+
+CNetChannel *CNetworkServer::FindNetChannel( const netadr_t& from )
+{
+	CPlayer *pl = FindPlayerByAddress( from );
+	if ( pl )
+		return &pl->m_NetChan;
+	return NULL;
+}
+
+CPlayer *CNetworkServer::FindPlayerByAddress( const netadr_t& adr )
+{
+	int c = m_Players.Count();
+	for ( int i = 0; i < c; ++i )
+	{
+		CPlayer *player = m_Players[ i ];
+		if ( player->GetRemoteAddress().CompareAdr( adr ) )
+			return player;
+	}
+	return NULL;
+}
+
+CPlayer *CNetworkServer::FindPlayerByNetChannel( INetChannel *chan )
+{
+	int c = m_Players.Count();
+	for ( int i = 0; i < c; ++i )
+	{
+		CPlayer *player = m_Players[ i ];
+		if ( &player->m_NetChan == chan )
+			return player;
+	}
+	return NULL;
+}
+
+#define SPEW_MESSAGES 
+
+#if defined( SPEW_MESSAGES )
+#define SM_SPEW_MESSAGE( code, remote ) \
+	Warning( "Message:  %s from '%s'\n", #code, remote );
+#else
+#define SM_SPEW_MESSAGE( code, remote ) 
+#endif
+// process a connectionless packet
+bool CNetworkServer::ProcessConnectionlessPacket( CNetPacket *packet )
+{
+	int code = packet->m_Message.ReadByte();
+	switch ( code )
+	{
+	case c2s_connect:
+		{
+			SM_SPEW_MESSAGE( c2s_connect, packet->m_From.ToString() );
+
+			CPlayer *pl = FindPlayerByAddress( packet->m_From );
+			if ( pl )
+			{
+				Warning( "Player already exists for %s\n", packet->m_From.ToString() );
+			}
+			else
+			{
+				// Creates the connection
+				pl = new CPlayer( this, packet->m_From );
+				m_Players.AddToTail( pl );
+
+				// Now send the conn accepted message
+				AcceptConnection( packet->m_From );
+			}
+		}
+		break;
+	default:
+		{
+			Warning( "CNetworkServer::ProcessConnectionlessPacket:  Unknown code '%i' from '%s'\n",
+				code, packet->m_From.ToString() );
+		}
+		break;
+	}
+
+	return true;
+}
+
+
+void CNetworkServer::AcceptConnection( const netadr_t& remote )
+{
+	byte data[ 512 ];
+	bf_write buf( "CNetworkServer::AcceptConnection", data, sizeof( data ) );
+
+	buf.WriteLong( -1 );
+	buf.WriteByte( s2c_connect_accept );
+
+	m_pSocket->SendTo( remote, buf.GetData(), buf.GetNumBytesWritten() );
+}
+
+void CNetworkServer::ReadPackets( void )
+{
+	UDP_ProcessSocket( m_pSocket, this, this );
+
+	int c = m_Players.Count();
+	for ( int i = c - 1; i >= 0 ; --i )
+	{
+		if ( m_Players[ i ]->m_bMarkedForDeletion )
+		{
+			CPlayer *pl = m_Players[ i ];
+			m_Players.Remove( i );
+			delete pl;
+		}
+	}
+}
+
+void CNetworkServer::SendUpdates()
+{
+	int c = m_Players.Count();
+	for ( int i = 0; i < c; ++i )
+	{
+		m_Players[ i ]->SendUpdate();
+	}
+}
+
+void CNetworkServer::OnConnectionStarted( INetChannel *pChannel )
+{
+	// Create a network event
+	NetworkConnectionEvent_t *pConnection = g_pNetworkSystemImp->CreateNetworkEvent< NetworkConnectionEvent_t >( );
+	pConnection->m_nType = NETWORK_EVENT_CONNECTED;
+	pConnection->m_pChannel = pChannel;
+}
+
+void CNetworkServer::OnConnectionClosing( INetChannel *pChannel, char const *reason )
+{
+	Warning( "OnConnectionClosing '%s'\n", reason );
+
+	CPlayer *pPlayer = FindPlayerByNetChannel( pChannel );
+	if ( pPlayer )
+	{
+		pPlayer->Shutdown();
+	}
+
+	// Create a network event
+	NetworkDisconnectionEvent_t *pDisconnection = g_pNetworkSystemImp->CreateNetworkEvent< NetworkDisconnectionEvent_t >( );
+	pDisconnection->m_nType = NETWORK_EVENT_DISCONNECTED;
+	pDisconnection->m_pChannel = pChannel;
+}
+
+void CNetworkServer::OnPacketStarted( int inseq, int outseq )
+{
+}
+
+void CNetworkServer::OnPacketFinished()
+{
+}
+
+
+//-----------------------------------------------------------------------------
+//
+// Implementation of CPlayer
+//
+//-----------------------------------------------------------------------------
+CPlayer::CPlayer( CNetworkServer *server, netadr_t& remote ) :
+	m_bMarkedForDeletion( false )
+{
+	m_NetChan.Setup( true, &remote, server->m_pSocket, "player", server );
+}
+
+void CPlayer::Shutdown()
+{
+	m_bMarkedForDeletion = true;
+	m_NetChan.Shutdown( "received disconnect\n" );
+}
+
+void CPlayer::SendUpdate()
+{
+	if ( m_NetChan.CanSendPacket() )
+	{
+		m_NetChan.SendDatagram( NULL );
+	}
+}
+
+
+
diff --git a/networksystem/networkserver.h b/networksystem/networkserver.h
new file mode 100644
index 0000000..bd88b5b
--- /dev/null
+++ b/networksystem/networkserver.h
@@ -0,0 +1,86 @@
+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+//===========================================================================//
+
+#ifndef NETWORKSERVER_H
+#define NETWORKSERVER_H
+
+#include "networksystem/inetworksystem.h"
+#include "netchannel.h"
+
+
+//-----------------------------------------------------------------------------
+// Forward declarations
+//-----------------------------------------------------------------------------
+class CPlayer;
+
+
+//-----------------------------------------------------------------------------
+// Server class
+//-----------------------------------------------------------------------------
+class CNetworkServer : public IConnectionlessPacketHandler, public INetworkMessageHandler, public ILookupChannel
+{
+public:
+	CNetworkServer( );
+	virtual ~CNetworkServer();
+
+	bool Init( int nServerPort );
+	void Shutdown();
+
+	// IConnectionlessPacketHandler
+	virtual bool	ProcessConnectionlessPacket( CNetPacket *packet );	// process a connectionless packet
+	
+	// INetworkMessageHandler
+	virtual void	OnConnectionClosing( INetChannel *channel, char const *reason );
+	virtual void	OnConnectionStarted( INetChannel *channel );
+
+	virtual void	OnPacketStarted( int inseq, int outseq );
+	virtual void	OnPacketFinished();
+
+	// ILookupChannel
+    virtual CNetChannel *FindNetChannel( const netadr_t& from ) ;
+
+	void ReadPackets();
+	void SendUpdates();
+	void AcceptConnection( const netadr_t& remote );
+
+	CPlayer *FindPlayerByAddress( const netadr_t& adr );
+	CPlayer *FindPlayerByNetChannel( INetChannel *chan );
+
+	CUDPSocket *m_pSocket;
+
+	CUtlVector< CPlayer * >	m_Players;
+};
+
+
+//-----------------------------------------------------------------------------
+// Represents a connected player to the server
+//-----------------------------------------------------------------------------
+class CPlayer
+{
+public:
+	CPlayer( CNetworkServer *server, netadr_t& remote );
+
+	void			SendUpdate();
+
+	const netadr_t		&GetRemoteAddress()
+	{
+		return m_NetChan.GetRemoteAddress();
+	}
+
+	char const *GetName()
+	{
+		return "Foozle";
+	}
+
+	void			Shutdown();
+
+	CNetChannel		m_NetChan;
+	bool			m_bMarkedForDeletion;
+};
+
+
+#endif // NETWORKSERVER_H
+
diff --git a/networksystem/networksystem.cpp b/networksystem/networksystem.cpp
new file mode 100644
index 0000000..b8650ec
--- /dev/null
+++ b/networksystem/networksystem.cpp
@@ -0,0 +1,491 @@
+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+//===========================================================================//
+
+#include "networksystem.h"
+#include "filesystem.h"
+#include "UDP_Socket.h"
+#include "sm_protocol.h"
+#include "NetChannel.h"
+#include "UDP_Process.h"
+#include <winsock.h>
+#include "networkclient.h"
+#include "networkserver.h"
+#include "networksystem/inetworkmessage.h"
+#include "mathlib/mathlib.h"
+#include "tier2/tier2.h"
+
+
+//-----------------------------------------------------------------------------
+// Singleton instance
+//-----------------------------------------------------------------------------
+static CNetworkSystem g_NetworkSystem;
+CNetworkSystem *g_pNetworkSystemImp = &g_NetworkSystem; 
+EXPOSE_SINGLE_INTERFACE_GLOBALVAR( CNetworkSystem, INetworkSystem, 
+						NETWORKSYSTEM_INTERFACE_VERSION, g_NetworkSystem );
+
+
+//-----------------------------------------------------------------------------
+// Constructor, destructor
+//-----------------------------------------------------------------------------
+CNetworkSystem::CNetworkSystem()
+{
+	m_bWinsockInitialized = false;
+	m_bNetworkEventCreated = false;
+	m_bInMidPacket = false;
+	m_pServer = NULL;
+	m_pClient = NULL;
+	m_nGroupBits = 1;
+	m_nTypeBits = LargestPowerOfTwoLessThanOrEqual( net_num_messages );
+}
+
+CNetworkSystem::~CNetworkSystem()
+{
+}
+
+
+//-----------------------------------------------------------------------------
+// Initialization, shutdown
+//-----------------------------------------------------------------------------
+InitReturnVal_t CNetworkSystem::Init()
+{
+	InitReturnVal_t nRetVal = BaseClass::Init();
+	if ( nRetVal != INIT_OK )
+		return nRetVal;
+
+	// initialize winsock 2.0
+	WSAData wsaData;
+	
+	if ( WSAStartup( MAKEWORD(2,0), &wsaData ) != 0 )
+	{
+		Warning( "Error! Failed to load network socket library.\n");
+		return INIT_OK;
+	}
+	else
+	{
+		m_bWinsockInitialized = true;
+	}
+
+	LPHOSTENT lp = gethostbyname("localhost");
+	if ( !lp )
+	{
+		Warning( "Error! Failed to query local host info\n");
+		return INIT_OK;
+	}
+	m_LocalHostName = lp->h_name;
+
+	lp = gethostbyname( m_LocalHostName );
+ 	if ( !lp )
+	{
+		Warning( "Error! Failed to query local host info\n");
+		return INIT_OK;
+	}
+
+	sockaddr ip;
+	m_LocalAddressString = inet_ntoa( *((in_addr*)(lp->h_addr_list[0])) );
+	StringToSockaddr( m_LocalAddressString, &ip );
+	m_LocalAddress.SetFromSockadr( &ip );
+	return INIT_OK;
+}
+
+void CNetworkSystem::Shutdown()
+{
+	if ( m_bWinsockInitialized )
+	{
+		WSACleanup();
+	}
+	CleanupNetworkMessages();
+	BaseClass::Shutdown();
+}
+
+
+//-----------------------------------------------------------------------------
+// Connect, disconnect
+//-----------------------------------------------------------------------------
+bool CNetworkSystem::Connect( CreateInterfaceFn factory )
+{
+	if ( !BaseClass::Connect( factory ) )
+		return false;
+
+	if ( !g_pFullFileSystem )
+	{
+		Warning( "The network system requires the filesystem to run!\n" );
+		return false;
+	}
+
+	return INIT_OK; 
+}
+
+
+//-----------------------------------------------------------------------------
+// Returns the current time
+//-----------------------------------------------------------------------------
+float CNetworkSystem::GetTime( void )
+{
+	return Plat_FloatTime();
+}
+
+
+//-----------------------------------------------------------------------------
+// Installs network message factories to be used with all connections
+//-----------------------------------------------------------------------------
+bool CNetworkSystem::RegisterMessage( INetworkMessage *pMessage )
+{
+	if ( m_pServer || m_pClient )
+	{
+		Warning( "Cannot register messages after connection has started.\n" );
+		return false;
+	}
+
+	if ( pMessage->GetGroup() == 0 )
+	{
+		Warning( "Network message group 0 is reserved by the network system.\n" );
+		return false;
+	}
+
+	// Look for already registered message
+	if ( m_NetworkMessages.Find( pMessage ) >= 0 )
+		return false;
+
+	// Allocate more space in messages 
+	int nGroupBits = LargestPowerOfTwoLessThanOrEqual( pMessage->GetGroup() );
+	int nTypeBits = LargestPowerOfTwoLessThanOrEqual( pMessage->GetType() );
+	m_nGroupBits = max( nGroupBits, m_nGroupBits );
+	m_nTypeBits = max( nTypeBits, m_nTypeBits );
+
+	m_NetworkMessages.AddToTail( pMessage );
+	return true;
+}
+
+void CNetworkSystem::CleanupNetworkMessages( )
+{
+	int nCount = m_NetworkMessages.Count();
+	for ( int i = 0; i < nCount; ++i )
+	{
+		m_NetworkMessages[i]->Release();
+	}
+
+	m_NetworkMessages.RemoveAll();
+}
+
+
+//-----------------------------------------------------------------------------
+// Finds a network message given a particular message type
+//-----------------------------------------------------------------------------
+INetworkMessage* CNetworkSystem::FindNetworkMessage( int group, int type )
+{
+	int nCount = m_NetworkMessages.Count();
+	for (int i=0; i < nCount; i++ )
+	{
+		if ( ( m_NetworkMessages[i]->GetGroup() == group ) && ( m_NetworkMessages[i]->GetType() == type ) )
+			return m_NetworkMessages[i];
+	}
+	return NULL;
+}
+
+
+//-----------------------------------------------------------------------------
+// Purpose: 
+//-----------------------------------------------------------------------------
+bool CNetworkSystem::StringToSockaddr( const char *s, struct sockaddr *sadr )
+{
+	struct hostent	*h;
+	char	*colon;
+	char	copy[128];
+	
+	Q_memset (sadr, 0, sizeof(*sadr));
+	((struct sockaddr_in *)sadr)->sin_family = AF_INET;
+	((struct sockaddr_in *)sadr)->sin_port = 0;
+
+	Q_strncpy (copy, s, sizeof( copy ) );
+	// strip off a trailing :port if present
+	for (colon = copy ; *colon ; colon++)
+		if (*colon == ':')
+		{
+			*colon = 0;
+			((struct sockaddr_in *)sadr)->sin_port = htons((short)atoi(colon+1));	
+		}
+	
+	if (copy[0] >= '0' && copy[0] <= '9' && Q_strstr( copy, "." ) )
+	{
+		*(int *)&((struct sockaddr_in *)sadr)->sin_addr = inet_addr(copy);
+	}
+	else
+	{
+//		if ( net_nodns )
+//			return false;	// DNS names disabled
+
+		if ( (h = gethostbyname(copy)) == NULL )
+			return false;
+
+		*(int *)&((struct sockaddr_in *)sadr)->sin_addr = *(int *)h->h_addr_list[0];
+	}
+	
+	return true;
+}
+
+
+//-----------------------------------------------------------------------------
+// Returns the local address
+//-----------------------------------------------------------------------------
+const char* CNetworkSystem::GetLocalHostName( void ) const
+{
+	return m_LocalHostName;
+}
+
+const char* CNetworkSystem::GetLocalAddress( void ) const
+{
+	return m_LocalAddressString;
+}
+
+
+//-----------------------------------------------------------------------------
+// Start, shutdown a server
+//-----------------------------------------------------------------------------
+bool CNetworkSystem::StartServer( unsigned short nServerListenPort )
+{
+	if ( !m_bWinsockInitialized )
+		return false;
+
+	Assert( !m_pServer );
+	m_pServer = new CNetworkServer;
+	return m_pServer->Init( nServerListenPort );
+}
+
+void CNetworkSystem::ShutdownServer( )
+{
+	if ( m_pServer )
+	{
+		m_pServer->Shutdown();
+		delete m_pServer;
+		m_pServer = NULL;
+	}
+}
+
+
+//-----------------------------------------------------------------------------
+// Server update
+//-----------------------------------------------------------------------------
+void CNetworkSystem::ServerReceiveMessages()
+{
+	if ( m_pServer )
+	{
+		m_pServer->ReadPackets();
+	}
+}
+
+void CNetworkSystem::ServerSendMessages()
+{
+	if ( m_pServer )
+	{
+		m_pServer->SendUpdates();
+	}
+}
+
+
+//-----------------------------------------------------------------------------
+// Start, shutdown a client
+//-----------------------------------------------------------------------------
+bool CNetworkSystem::StartClient( unsigned short nClientListenPort )
+{
+	if ( !m_bWinsockInitialized )
+		return false;
+
+	Assert( !m_pClient );
+	m_pClient = new CNetworkClient;
+	return m_pClient->Init( nClientListenPort );
+}
+
+void CNetworkSystem::ShutdownClient( )
+{
+	if ( m_pClient )
+	{
+		m_pClient->Shutdown();
+		delete m_pClient;
+		m_pClient = NULL;
+	}
+}
+
+
+//-----------------------------------------------------------------------------
+// Server update
+//-----------------------------------------------------------------------------
+void CNetworkSystem::ClientReceiveMessages()
+{
+	if ( m_pClient )
+	{
+		m_pClient->ReadPackets();
+	}
+}
+
+void CNetworkSystem::ClientSendMessages()
+{
+	if ( m_pClient )
+	{
+		m_pClient->SendUpdate();
+	}
+}
+
+
+//-----------------------------------------------------------------------------
+// Server update
+//-----------------------------------------------------------------------------
+INetChannel* CNetworkSystem::ConnectClientToServer( const char *pServer, int nServerListenPort )
+{
+	if ( m_pClient )
+	{
+		if ( m_pClient->Connect( pServer, nServerListenPort ) )
+			return m_pClient->GetNetChannel();
+	}
+	return NULL;
+}
+
+void CNetworkSystem::DisconnectClientFromServer( INetChannel* pChannel )
+{
+	if ( m_pClient && ( m_pClient->GetNetChannel() == pChannel ) )
+	{
+		m_pClient->Disconnect();
+	}
+}
+
+
+//-----------------------------------------------------------------------------
+// Queues up a network packet
+//-----------------------------------------------------------------------------
+void CNetworkSystem::EnqueueConnectionlessNetworkPacket( CNetPacket *pPacket, IConnectionlessPacketHandler *pHandler )
+{
+	int i = m_PacketQueue.AddToTail( );
+
+	PacketInfo_t& info = m_PacketQueue[i];
+	info.m_pPacket = pPacket;
+	info.m_pHandler = pHandler;
+	info.m_pNetChannel = NULL;
+}
+
+void CNetworkSystem::EnqueueNetworkPacket( CNetPacket *pPacket, CNetChannel *pNetChannel )
+{
+	int i = m_PacketQueue.AddToTail( );
+
+	PacketInfo_t& info = m_PacketQueue[i];
+	info.m_pPacket = pPacket;
+	info.m_pHandler = NULL;
+	info.m_pNetChannel = pNetChannel;
+}
+
+
+//-----------------------------------------------------------------------------
+// Network event iteration helpers
+//-----------------------------------------------------------------------------
+bool CNetworkSystem::StartProcessingNewPacket()
+{
+	PacketInfo_t& info = m_PacketQueue[ m_nProcessingPacket ];
+	if ( info.m_pHandler )
+	{
+		UDP_ProcessConnectionlessPacket( info.m_pPacket, info.m_pHandler );
+		return false;
+	}
+
+	if ( !info.m_pNetChannel )
+	{
+		// Not an error that may happen during connect or disconnect
+		Warning( "Sequenced packet without connection from %s\n" , info.m_pPacket->m_From.ToString() );
+		return false;
+	}
+
+	return info.m_pNetChannel->StartProcessingPacket( info.m_pPacket );
+}
+
+bool CNetworkSystem::AdvanceProcessingNetworkPacket( )
+{
+	m_PacketQueue[ m_nProcessingPacket ].m_pPacket->Release();
+	m_PacketQueue[ m_nProcessingPacket ].m_pPacket = NULL;
+
+	++m_nProcessingPacket;
+	bool bOverflowed = ( m_nProcessingPacket >= m_PacketQueue.Count() );
+	if ( bOverflowed )
+	{
+		m_PacketQueue.RemoveAll();
+		m_nProcessingPacket = 0;
+	}
+	return !bOverflowed;
+}
+
+
+//-----------------------------------------------------------------------------
+// Network event iteration
+//-----------------------------------------------------------------------------
+NetworkEvent_t *CNetworkSystem::FirstNetworkEvent( )
+{
+	Assert( !m_bInMidPacket && !m_nProcessingPacket );
+	m_nProcessingPacket = 0;
+	m_bInMidPacket = false;
+	return NextNetworkEvent();
+}
+
+NetworkEvent_t *CNetworkSystem::NextNetworkEvent( )
+{
+	int nPacketCount = m_PacketQueue.Count();
+	if ( m_nProcessingPacket >= nPacketCount )
+		return NULL;
+
+	while( true )
+	{
+		// Continue processing the packet we're currently on
+		if ( m_bInMidPacket )
+		{
+			PacketInfo_t& info = m_PacketQueue[ m_nProcessingPacket ];
+			while( info.m_pNetChannel->ProcessPacket( info.m_pPacket ) )
+			{
+				Assert( m_bNetworkEventCreated );
+				m_bNetworkEventCreated = false;
+				return (NetworkEvent_t*)m_EventMessageBuffer;
+			}
+			info.m_pNetChannel->EndProcessingPacket( info.m_pPacket );
+			m_bInMidPacket = false;
+
+			if ( !AdvanceProcessingNetworkPacket() )
+				return NULL;
+		}
+
+		// Keep reading packets until we find one that either generates an event,
+		// one that encounters a packet we need to process, or we exhaust the event queue
+		while( !StartProcessingNewPacket() )
+		{
+			bool bOverflowed = !AdvanceProcessingNetworkPacket();
+
+			if ( m_bNetworkEventCreated )
+			{
+				m_bNetworkEventCreated = false;
+				return (NetworkEvent_t*)m_EventMessageBuffer;
+			}
+
+			if ( bOverflowed )
+				return NULL;
+		}
+
+		m_bInMidPacket = true;
+	}
+}
+
+
+//-----------------------------------------------------------------------------
+// Network event creation
+//-----------------------------------------------------------------------------
+NetworkEvent_t* CNetworkSystem::CreateNetworkEvent( int nSizeInBytes )
+{
+	Assert( nSizeInBytes <= sizeof( m_EventMessageBuffer ) );
+
+	// If this assertion fails, it means two or more network events were created
+	// before the main network event loop had a chance to inform external code
+	Assert( !m_bNetworkEventCreated );
+	m_bNetworkEventCreated = true;
+	return ( NetworkEvent_t* )m_EventMessageBuffer;
+}
+
+bool CNetworkSystem::IsNetworkEventCreated()
+{
+	return m_bNetworkEventCreated;
+}
+	
diff --git a/networksystem/networksystem.h b/networksystem/networksystem.h
new file mode 100644
index 0000000..894393d
--- /dev/null
+++ b/networksystem/networksystem.h
@@ -0,0 +1,172 @@
+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+//===========================================================================//
+
+#ifndef NETWORKSYSTEM_H
+#define NETWORKSYSTEM_H
+
+#ifdef _WIN32
+#pragma once
+#endif
+
+#include "networksystem/inetworksystem.h"
+#include "tier1/utlvector.h"
+#include "tier1/bitbuf.h"
+#include "sm_protocol.h"
+#include "networksystem/inetworkmessage.h"
+#include "tier1/netadr.h"
+#include "tier1/utlstring.h"
+#include "tier2/tier2.h"
+
+
+//-----------------------------------------------------------------------------
+// Forward declarations
+//-----------------------------------------------------------------------------
+class CNetworkServer;
+class CNetworkClient;
+class IConnectionlessPacketHandler;
+class CNetChannel;
+enum SystemNetworkMessageType_t;
+
+
+//-----------------------------------------------------------------------------
+// Global interfaces
+//-----------------------------------------------------------------------------
+class CNetworkSystem;
+extern CNetworkSystem *g_pNetworkSystemImp;
+
+
+//-----------------------------------------------------------------------------
+// Implementation of the network system
+//-----------------------------------------------------------------------------
+class CNetworkSystem : public CTier2AppSystem< INetworkSystem >
+{
+	typedef CTier2AppSystem< INetworkSystem > BaseClass;
+
+public:
+	// Constructor, destructor
+	CNetworkSystem();
+	virtual ~CNetworkSystem();
+
+	// Inherited from IAppSystem
+	virtual bool Connect( CreateInterfaceFn factory );
+	virtual InitReturnVal_t Init();
+	virtual void Shutdown();
+
+	// Inherited from INetworkSystem
+	virtual bool RegisterMessage( INetworkMessage *msg );
+	virtual bool StartServer( unsigned short nServerListenPort );
+	virtual void ShutdownServer( );
+	virtual void ServerReceiveMessages();
+	virtual void ServerSendMessages();
+
+	virtual bool StartClient( unsigned short nClientListenPort );
+	virtual void ShutdownClient( );
+	virtual void ClientSendMessages();
+	virtual void ClientReceiveMessages();
+	virtual INetChannel* ConnectClientToServer( const char *pServer, int nServerListenPort );
+	virtual void DisconnectClientFromServer( INetChannel* pChan );
+	virtual NetworkEvent_t *FirstNetworkEvent( );
+	virtual NetworkEvent_t *NextNetworkEvent( );
+	virtual const char* GetLocalHostName( void ) const;
+	virtual const char* GetLocalAddress( void ) const;
+
+	// Methods internal for use in networksystem library
+
+	// Method to allow systems to add network events received
+	NetworkEvent_t* CreateNetworkEvent( int nSizeInBytes );
+	template< class T > T* CreateNetworkEvent();
+	bool IsNetworkEventCreated();
+
+	// Finds a network message given a particular message type
+	INetworkMessage* FindNetworkMessage( int group, int type );
+
+	// Returns the number of bits to encode the type + group with
+	int GetTypeBitCount() const;
+	int GetGroupBitCount() const;
+
+	// Returns the current time
+	float GetTime( void );
+
+	// Converts a string to a socket address 
+	bool StringToSockaddr( const char *s, struct sockaddr *sadr );
+
+	// Queues up a network packet
+	void EnqueueConnectionlessNetworkPacket( CNetPacket *pPacket, IConnectionlessPacketHandler *pHandler );
+	void EnqueueNetworkPacket( CNetPacket *pPacket, CNetChannel *pNetChannel );
+
+private:
+	struct PacketInfo_t
+	{
+		CNetPacket *m_pPacket;
+		IConnectionlessPacketHandler *m_pHandler;
+		CNetChannel *m_pNetChannel;
+	};
+
+	// Network event iteration helpers
+	bool StartProcessingNewPacket();
+	bool AdvanceProcessingNetworkPacket( );
+	void CleanupNetworkMessages( );
+
+	bool m_bWinsockInitialized : 1;
+	bool m_bNetworkEventCreated : 1;
+	bool m_bInMidPacket : 1;
+	int m_nTypeBits;
+	int m_nGroupBits;
+	netadr_t m_LocalAddress;
+	CUtlString m_LocalAddressString;
+	CUtlString m_LocalHostName;
+	CNetworkServer *m_pServer;
+	CNetworkClient *m_pClient;
+	unsigned char m_EventMessageBuffer[256];
+	CUtlVector<PacketInfo_t> m_PacketQueue;
+	int m_nProcessingPacket;
+	CUtlVector<INetworkMessage*> m_NetworkMessages;
+};
+
+
+//-----------------------------------------------------------------------------
+// Inline methods
+//-----------------------------------------------------------------------------
+template< class T > 
+T* CNetworkSystem::CreateNetworkEvent()
+{
+	// Increase the size of m_EventMessageBuffer if this assertion fails
+	COMPILE_TIME_ASSERT( sizeof(T) <= sizeof( m_EventMessageBuffer ) );
+	return (T*)CreateNetworkEvent( sizeof(T) );
+}
+
+	
+//-----------------------------------------------------------------------------
+// Returns the number of bits to encode the type + group with
+//-----------------------------------------------------------------------------
+inline int CNetworkSystem::GetTypeBitCount() const
+{
+	return m_nTypeBits;
+}
+
+inline int CNetworkSystem::GetGroupBitCount() const
+{
+	return m_nGroupBits;
+}
+
+	
+//-----------------------------------------------------------------------------
+// Writes a system network message
+//-----------------------------------------------------------------------------
+inline void WriteSystemNetworkMessage( bf_write &msg, SystemNetworkMessageType_t type )
+{
+	msg.WriteUBitLong( net_group_networksystem, g_pNetworkSystemImp->GetGroupBitCount() );
+	msg.WriteUBitLong( type, g_pNetworkSystemImp->GetTypeBitCount() );
+}
+
+inline void WriteNetworkMessage( bf_write &msg, INetworkMessage *pNetworkMessage )
+{
+	msg.WriteUBitLong( pNetworkMessage->GetGroup(), g_pNetworkSystemImp->GetGroupBitCount() );
+	msg.WriteUBitLong( pNetworkMessage->GetType(), g_pNetworkSystemImp->GetTypeBitCount() );
+}
+
+#endif // NETWORKSYSTEM_H
+
diff --git a/networksystem/networksystem.vpc b/networksystem/networksystem.vpc
new file mode 100644
index 0000000..5146263
--- /dev/null
+++ b/networksystem/networksystem.vpc
@@ -0,0 +1,54 @@
+//-----------------------------------------------------------------------------
+//	NETWORKSYSTEM.VPC
+//
+//	Project Script
+//-----------------------------------------------------------------------------
+
+$Macro SRCDIR		".."
+$Macro OUTBINDIR	"$SRCDIR\..\game\bin"
+
+$Include "$SRCDIR\vpc_scripts\source_dll_base.vpc"
+
+$Configuration
+{
+	$Compiler
+	{
+		$PreprocessorDefinitions			"$BASE;NETWORKSYSTEM_EXPORTS"
+	}
+
+	$Linker
+	{
+		$AdditionalDependencies				"$BASE winmm.lib ws2_32.lib"
+	}
+}
+
+$Project "Networksystem"
+{
+	$Folder	"Source Files"
+	{
+		$File	"netchannel.cpp"
+		$File	"netchannel.h"
+		$File	"networkclient.cpp"
+		$File	"networkclient.h"
+		$File	"networkserver.cpp"
+		$File	"networkserver.h"
+		$File	"networksystem.cpp"
+		$File	"networksystem.h"
+		$File	"sm_protocol.h"
+		$File	"udp_process.cpp"
+		$File	"udp_process.h"
+		$File	"udp_socket.cpp"
+		$File	"udp_socket.h"
+	}
+
+	$Folder	"Interface"
+	{
+		$File	"$SRCDIR\common\networksystem\inetworkmessage.h"
+		$File	"$SRCDIR\common\networksystem\inetworksystem.h"
+	}
+
+	$Folder "Link Libraries"
+	{
+		$Lib tier2
+	}
+}
diff --git a/networksystem/sm_protocol.h b/networksystem/sm_protocol.h
new file mode 100644
index 0000000..a4f28f9
--- /dev/null
+++ b/networksystem/sm_protocol.h
@@ -0,0 +1,49 @@
+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+//=============================================================================
+
+#ifndef SM_PROTOCOL_H
+#define SM_PROTOCOL_H
+#ifdef _WIN32
+#pragma once
+#endif
+
+enum
+{
+	CONNECTIONLESS_HEADER = 0xffffffff,
+};
+
+// Connectionless messages
+enum
+{
+	c2s_connect = 1,
+
+	c2s_num_messages
+};
+
+enum
+{
+	s2c_connect_accept = 1,
+	s2c_connect_reject,
+
+	s2c_num_messages
+};
+
+enum NetworkMessageGroup_t
+{
+	net_group_networksystem = 0
+};
+
+// Networksystem internal messages for use during valid connection
+enum SystemNetworkMessageType_t
+{
+	net_nop 		= 0,			// nop command used for padding
+	net_disconnect	= 1,			// disconnect, last message in connection
+
+	net_num_messages
+};
+
+
+#endif // SM_PROTOCOL_H
diff --git a/networksystem/udp_process.cpp b/networksystem/udp_process.cpp
new file mode 100644
index 0000000..92d08c5
--- /dev/null
+++ b/networksystem/udp_process.cpp
@@ -0,0 +1,134 @@
+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+//===========================================================================//
+
+#include "tier1/utlbuffer.h"
+#include "UDP_Socket.h"
+#include "NetChannel.h"
+#include "sm_protocol.h"
+#include "networksystem.h"
+
+
+//-----------------------------------------------------------------------------
+// Allocates memory for packets
+//-----------------------------------------------------------------------------
+static CUtlMemoryPool s_PacketBufferAlloc( NET_MAX_MESSAGE, 8, CUtlMemoryPool::GROW_SLOW );
+DEFINE_FIXEDSIZE_ALLOCATOR( CNetPacket, 32, CUtlMemoryPool::GROW_SLOW );
+
+
+//-----------------------------------------------------------------------------
+// Constructor, destructor
+//-----------------------------------------------------------------------------
+CNetPacket::CNetPacket()
+{
+	m_pData = reinterpret_cast<byte*>( s_PacketBufferAlloc.Alloc() );
+	m_nRefCount = 1;
+}
+
+CNetPacket::~CNetPacket()
+{
+	s_PacketBufferAlloc.Free( m_pData );
+}
+
+void CNetPacket::AddRef()
+{
+	++m_nRefCount;
+}
+
+void CNetPacket::Release()
+{
+	if ( --m_nRefCount <= 0 )
+	{
+		delete this;
+	}
+}
+	
+bool UDP_ReceiveDatagram( CUDPSocket *pSocket, CNetPacket* pPacket )
+{
+	Assert( pPacket );
+
+	netadr_t packetFrom;
+	CUtlBuffer buf( pPacket->m_pData, NET_MAX_MESSAGE );
+	if ( pSocket->RecvFrom( packetFrom, buf ) )
+	{
+		pPacket->m_From = packetFrom;
+		pPacket->m_nSizeInBytes = buf.TellPut();
+		return true;
+	}
+	return false;
+}
+
+CNetPacket *UDP_GetPacket( CUDPSocket *pSocket )
+{
+	CNetPacket *pPacket = new CNetPacket;
+
+	// setup new packet
+	pPacket->m_From.SetType( NA_IP );
+	pPacket->m_From.Clear();
+	pPacket->m_flReceivedTime = g_pNetworkSystemImp->GetTime();
+	pPacket->m_pSource = pSocket;	
+	pPacket->m_nSizeInBytes = 0;
+	pPacket->m_Message.SetDebugName("inpacket.message");
+
+	// then check UDP data 
+	if ( !UDP_ReceiveDatagram( pSocket, pPacket ) )
+	{
+		delete pPacket;
+		return NULL;
+	}
+		
+	Assert( pPacket->m_nSizeInBytes ); 
+	
+	// prepare bitbuffer for reading packet with new size
+	pPacket->m_Message.StartReading( pPacket->m_pData, pPacket->m_nSizeInBytes );
+	return pPacket;
+}
+
+void UDP_ProcessSocket( CUDPSocket *pSocket, IConnectionlessPacketHandler *pHandler, ILookupChannel *pLookup )
+{
+	CNetPacket *pPacket;
+	
+	Assert( pSocket );
+
+	// Get datagrams from sockets
+	while ( ( pPacket = UDP_GetPacket ( pSocket ) ) != NULL )
+	{
+		/*
+		if ( Filter_ShouldDiscard ( pPacket->m_From ) )	// filterning is done by network layer
+		{
+			Filter_SendBan( pPacket->m_From );	// tell them we aren't listening...
+			continue;
+		} 
+		*/
+
+		// Find the netchan it came from
+		if ( *(unsigned int *)pPacket->m_pData == CONNECTIONLESS_HEADER )
+		{
+			g_pNetworkSystemImp->EnqueueConnectionlessNetworkPacket( pPacket, pHandler );
+		}
+		else
+		{
+			INetChannel *pNetChan = pLookup->FindNetChannel( pPacket->m_From );
+			g_pNetworkSystemImp->EnqueueNetworkPacket( pPacket, static_cast<CNetChannel*>( pNetChan ) );
+		}
+	}
+}
+
+void UDP_ProcessConnectionlessPacket( CNetPacket *pPacket, IConnectionlessPacketHandler *pHandler )
+{
+	// check for connectionless packet (0xffffffff) first
+	Assert( *(unsigned int *)pPacket->m_pData == CONNECTIONLESS_HEADER );
+
+	pPacket->m_Message.ReadLong();	// read the -1
+
+	/*
+	if ( net_showudp.GetInt() )
+	{
+		Msg("UDP <- %s: sz=%i OOB '%c'\n", info.m_pPacket->m_From.ToString(), pPacket->m_nSizeInBytes, pPacket->m_pData[4] );
+	}
+	*/
+
+	pHandler->ProcessConnectionlessPacket( pPacket );
+}
diff --git a/networksystem/udp_process.h b/networksystem/udp_process.h
new file mode 100644
index 0000000..73fca50
--- /dev/null
+++ b/networksystem/udp_process.h
@@ -0,0 +1,21 @@
+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+//=============================================================================
+
+#ifndef UDP_PROCESS_H
+#define UDP_PROCESS_H
+#ifdef _WIN32
+#pragma once
+#endif
+
+class CUDPSocket;
+class IConnectionlessPacketHandler;
+class ILookupChannel;
+class CNetPacket;
+
+void UDP_ProcessSocket( CUDPSocket *socket, IConnectionlessPacketHandler *handler, ILookupChannel *lookup );
+void UDP_ProcessConnectionlessPacket( CNetPacket *pPacket, IConnectionlessPacketHandler *pHandler );
+
+#endif // UDP_PROCESS_H
diff --git a/networksystem/udp_socket.cpp b/networksystem/udp_socket.cpp
new file mode 100644
index 0000000..53f2fda
--- /dev/null
+++ b/networksystem/udp_socket.cpp
@@ -0,0 +1,120 @@
+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+//===========================================================================//
+
+#include <winsock.h>
+#include "udp_socket.h"
+#include "tier1/utlbuffer.h"
+#include "tier1/strtools.h"
+
+class CUDPSocket::CImpl	
+{
+public:
+	struct sockaddr_in	m_SocketIP;
+};
+
+CUDPSocket::CUDPSocket( ) :
+	m_socketIP(),
+	m_Socket( INVALID_SOCKET ),
+	m_Port( 0 ),
+	m_pImpl( new CImpl )
+{
+	Q_memset( &m_socketIP, 0, sizeof( m_socketIP ) );
+}
+
+CUDPSocket::~CUDPSocket()
+{
+	delete m_pImpl;
+}
+
+bool CUDPSocket::Init( unsigned short nBindToPort )
+{
+	m_Port = nBindToPort;
+	struct sockaddr_in	address;
+
+	m_Socket = socket( PF_INET, SOCK_DGRAM, IPPROTO_UDP );
+	if ( m_Socket == INVALID_SOCKET )
+		return false;
+
+	address = m_pImpl->m_SocketIP;
+	address.sin_family = AF_INET;
+	address.sin_port = htons( m_Port );
+	address.sin_addr.S_un.S_addr = INADDR_ANY;
+
+	if ( SOCKET_ERROR == bind( m_Socket, ( struct sockaddr * )&address, sizeof( address ) ) )
+	{
+		return false;
+	}
+
+	// Set to non-blocking i/o
+	unsigned long value = 1;
+	if ( SOCKET_ERROR == ioctlsocket( m_Socket, FIONBIO, &value ) )
+	{
+		return false;
+	}
+
+	return true;
+}
+
+void CUDPSocket::Shutdown()
+{
+	if ( m_Socket != INVALID_SOCKET )
+	{
+		closesocket( static_cast<unsigned int>( m_Socket )); 
+	}
+}
+
+bool CUDPSocket::RecvFrom( netadr_t& packet_from, CUtlBuffer& data )
+{
+	sockaddr from;
+	int nFromLen = sizeof( from );
+
+	int nMaxBytesToRead = data.Size() - data.TellPut();
+	char *pBuffer = (char*)data.PeekPut();
+
+	int nBytesRead = recvfrom( m_Socket, pBuffer, nMaxBytesToRead, 0, &from, &nFromLen );
+	if ( nBytesRead == SOCKET_ERROR )
+	{
+		int nError = WSAGetLastError();
+		if ( nError != WSAEWOULDBLOCK )
+		{
+			Warning( "Socket error '%i'\n", nError );
+		}
+		return false;
+	}
+
+	packet_from.SetFromSockadr( &from );
+	data.SeekPut( CUtlBuffer::SEEK_CURRENT, nBytesRead );
+	return true;
+}
+
+bool CUDPSocket::SendTo( const netadr_t &recipient, const CUtlBuffer& data  )
+{
+	return SendTo( recipient, (const byte *)data.Base(), (size_t)data.TellPut() );
+}
+
+bool CUDPSocket::SendTo( const netadr_t &recipient, const byte *data, size_t datalength )
+{
+	sockaddr dest;
+	recipient.ToSockadr( &dest );
+
+	// Send data
+	int bytesSent = sendto
+		(
+		m_Socket, 
+		(const char *)data, 
+		(int)datalength, 
+		0, 
+		reinterpret_cast< const sockaddr * >( &dest ), 
+		sizeof( dest ) 
+		);
+
+	if ( SOCKET_ERROR == bytesSent )
+	{
+		return false;
+	}
+
+	return true;
+}
diff --git a/networksystem/udp_socket.h b/networksystem/udp_socket.h
new file mode 100644
index 0000000..8f7c88a
--- /dev/null
+++ b/networksystem/udp_socket.h
@@ -0,0 +1,45 @@
+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+//=============================================================================
+
+#ifndef UDP_SOCKET_H
+#define UDP_SOCKET_H
+#ifdef _WIN32
+#pragma once
+#endif
+
+#include "tier1/netadr.h"
+#include "tier0/basetypes.h"
+
+class CUtlBuffer;
+
+// Creates a non-blocking UPD socket
+class CUDPSocket
+{
+public:
+	CUDPSocket();
+	~CUDPSocket();
+
+	bool Init( unsigned short bindToPort );
+	void Shutdown();
+
+	bool RecvFrom( netadr_t& packet_from, CUtlBuffer& data );
+	bool SendTo( const netadr_t &recipient, const CUtlBuffer& data  );
+	bool SendTo( const netadr_t &recipient, const byte *data, size_t datalength );
+
+	bool IsValid() const { return m_Socket != 0; }
+
+protected:
+	bool CreateSocket (void);
+
+	class CImpl;
+	CImpl				*m_pImpl;
+
+	netadr_t			m_socketIP;
+	unsigned int		m_Socket;
+	unsigned short		m_Port;
+};
+
+#endif // UDP_SOCKET_H