#ifndef ns_rdt_h#define ns_rdt_h#include "udp.h"#include "ip.h"// RDT Header Structurestruct hdr_rdt {	int ack;     // is it ack packet?	int rej;	// is it rej packet?	int seq;     // rdt sequence number	int nbytes;  // bytes for rdt pkt	double time; // current time	int scale;   // scale (0-4) associated with data rates	// Packet header access functions        static int offset_;        inline static int& offset() { return offset_; }        inline static hdr_rdt* access(const Packet* p) {                return (hdr_rdt*) p->access(offset_);        }};// Used for Re-assemble segmented (by UDP) rdt packetstruct asm_rdt { 	int seq;     // rdt sequence number	int rbytes;  // currently received bytes	int tbytes;  // total bytes to receive for rdt packet};// rdtAgent Class definitionclass rdtAgent : public UdpAgent {public:	rdtAgent();	rdtAgent(packet_t);	virtual int supportMM() { return 1; }	virtual void enableMM() { support_mm_ = 1; }	virtual void sendmsg(int nbytes, const char *flags = 0);	void recv(Packet*, Handler*);protected:	int support_mm_; // set to 1 if above is MmAppprivate:	asm_rdt asm_info; // packet re-assembly information};#endif