Added original SDK code for Alien Swarm.

public/inetwork.h

@@ -0,0 +1,52 @@
+//========= Copyright <20> 1996-2005, Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+//=============================================================================//
+
+#ifndef INETWORK_H
+#define INETWORK_H
+#ifdef _WIN32
+#pragma once
+#endif
+
+class IConnectionlessPacketHandler;
+
+abstract_class INetwork
+{
+public:
+	virtual	~INetwork( void ) {};
+
+	virtual void Init( void ) = 0;
+	virtual void Config (bool multiplayer);	
+	virtual void IsMultiplayer( void ) = 0; // true = full MP mode, false = loopback SP mode
+	virtual void IsEnabled( void ) = 0;	
+
+	// shuts down Network, closes all UPD/TCP channels
+	virtual void Shutdown( void ) = 0;
+
+	// must be called each system frame to do any asynchronouse TCP stuff 
+	virtual void RunFrame( double time ) = 0;
+
+	virtual void ProcessSocket( netsrc_t sock, IConnectionlessPacketHandler * handler ) = 0;
+
+	virtual void OutOfBandPrintf(netsrc_t sock, netadr_t &adr, const char *format, ...) = 0;
+	virtual void SendConnectionless(netsrc_t sock, netadr_t &adr, unsigned char * data, int length ) = 0;
+
+	virtual void LogBadPacket(netpacket_t * packet) = 0;
+	
+	// Address conversion
+	virtual bool StringToAdr ( const char *s, netadr_t *a) = 0;
+
+	// Convert from host to network byte ordering
+	virtual unsigned short HostToNetShort( unsigned short us_in );
+
+	// and vice versa
+	virtual unsigned short NetToHostShort( unsigned short us_in );
+	
+
+	
+};
+
+
+#endif // INETWORK_H