/* -*- c++ -*-
   rcp.h

   Received-Based TCP (Receiver Side)

   Two agents: RcpAgent (receiver side) and RcpTap (sender side)
 */

#ifndef __rcp_h__
#define __rcp_h__

#include "tcp.h"
/*
 * The following definition can be put in tcp.h
 */
#define REPN (NSA*2)					// 3 blocks

#ifdef  NDEBUG
#undef  NDEBUG
#endif  

/*
 * Racker should ideally deal with only reliability & sequence of pkt to send
 */
class Racker {
    struct PKI { int seen; int req; double sent; int later; };
public:
    Racker();
    ~Racker();
    void reset(double wnd); 

    virtual int resequence(Packet *pkt);		// receive one packet
    int  request(int fid,int seq,double *t,int force=0);// request a token
    int  nextseq();					// next to send
    int  islost(int seq);				// loss detection
    void timeout();					// notify timeout

    inline int pipe()	   {return pipe_;}
    inline int buflen()	   {return int(blength_);}
    inline double buffer() {return (npacket_ ? blength_/npacket_ : 0.0);}

protected:
    void loseit(int seq);				// mark loss

    int  wndmask_, rcvnext_, maxseen_, maxreq_, bufsize_;
    int  pipe_;
    PKI *buf_;
    #define pki_(i) buf_[(i) & wndmask_]

    /*
     * statistics
     */ 
    double blength_;
    int    npacket_;
};

class RcpAgent : public TcpAgent {
public:
    RcpAgent(Racker *);
    virtual void reset();
    virtual int  command(int argc, const char*const* argv);
    virtual void sendmsg(int sz, AppData*, const char* flags = 0);
    virtual void recv(Packet *p, Handler *h);
    virtual void resume();

protected:
    virtual void delay_bind_init_all();
    virtual int  delay_bind_dispatch(const char *, const char *, TclObject *);

    virtual void send_one(void);
    virtual void send_much(int force, int reason, int maxburst);
    virtual void output(int seqno, int reason = 0);
    virtual void dupack_action();
    virtual void timeout(int tno);
    int  send_allowed(int seq);
    int  sendpkt(int seqno, int reason=0, int force=0);
    void rcp_eln(Packet *pkt);

    Racker   *racker_;

    TracedInt r_seqno_,o_seqno_,b_length_;
    enum {NORMAL_=0, FASTRECOV_, PASSIVE_, SLEEP_} state_;
    u_char timeout_, firstpkt_;
//  double pdrop_[1024];

    int rpq_[REPN], repnxt_;
    #define rep_(i) rpq_[(i) % REPN]
};

#endif/*__rcp_h__*/