/Users/yzchen/ns/ns-allinone-2.33/ns-2.33/tcp/scoreboard1.h

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/* 
 * TCP-Linux module for NS2 
 *
 * May 2006
 *
 * Author: Xiaoliang (David) Wei  (DavidWei@acm.org)
 *
 * NetLab, the California Institute of Technology 
 * http://netlab.caltech.edu
 *
 * Module: scoreboard1.h
 *      This is the header file for Scoreboard1 in TCP-Linux.
 *      We define the states of a packet in here (SKB_FLAG_*).
 *
 */

#ifndef ns_scoreboard1_h
#define ns_scoreboard1_h

//  Definition of the scoreboard class:
#include "tcp.h"

#define SKB_FLAG_INFLIGHT 0             /* in flight, new packets */
#define SKB_FLAG_SACKED 1               /* Acked by SACK block */
#define SKB_FLAG_LOST 2                 /* lost by FACK signal */
#define SKB_FLAG_RETRANSMITTED 4        /* in flight, but is retransmitted packets */

class ScoreBoardNode1 {
public:
        ScoreBoardNode1(int start, int end, char flag):
                flag_(flag),
                seq_(start),
                nxt_(end),
                next_in_queue_(NULL)
        {}
        inline char GetFlag() { return flag_; }

        inline int GetStart() { return seq_; }
        inline int GetEnd() { return (flag_==SKB_FLAG_RETRANSMITTED)?seq_:nxt_; }
        inline int GetLength() {return (flag_==SKB_FLAG_RETRANSMITTED)?1:(nxt_+1-seq_); }
        inline int GetRtx() { return retran_;}
        inline int GetSndNxt() { return nxt_; }
        inline void SetFlag(char flag) { if (flag_==SKB_FLAG_RETRANSMITTED) nxt_=seq_; flag_ = flag;}
        inline void SetBegin(int seq) { seq_=seq; }
        inline void Append(ScoreBoardNode1* next) {next_in_queue_ = next;}
        inline bool Inside(int seq) { return (flag_==SKB_FLAG_RETRANSMITTED)?(seq==seq_):((seq>=seq_) && (seq<=nxt_)); }
//        inline int Compare(int seq) { if (flag_==SKB_FLAG_RETRANSMITTED) return (seq-seq_); else if (seq<seq_) return -1; else if (seq>nxt_) return 1; else return 0;}
        inline int ShouldClean(int ackseq) 
        // return: 0: this block should not be touched; -1: the whole block should be deleted; 
        //      >0: the first # of packets should be deleted
        {
                if (ackseq<seq_) 
                        return 0;
                else if ((flag_==SKB_FLAG_RETRANSMITTED)||(ackseq>=nxt_)) return -1; 
                else return ackseq+1-seq_;
        }

        inline ScoreBoardNode1* GetNext() { return next_in_queue_; }

        inline bool Mergable() { return ((next_in_queue_) && (next_in_queue_->flag_!=SKB_FLAG_RETRANSMITTED) && (next_in_queue_->flag_ == flag_)); }
        //to check if the next packet can be merged to this packet

        void Merge() 
        { 
        //merge with the next packet: WARNING: call this function ONLY WHEN you check the validity by Mergable. 
                ScoreBoardNode1* next = next_in_queue_;
                nxt_ = next->nxt_;
                next_in_queue_ = next->next_in_queue_;
                delete next;
        }


        inline bool Splittable(int seq) { return (flag_!=SKB_FLAG_RETRANSMITTED) && (seq>seq_) && (seq<=nxt_);}
        //to check if a node can be split from seq.

        ScoreBoardNode1* Split(int seq) 
        {
        // split the current node by the seq; the new node starts is [seq, end of the block]; return the new node
        // WARNING: Make sure it is Splittable before this functionis called.
                ScoreBoardNode1* next = new ScoreBoardNode1(seq, nxt_, flag_);
                next->next_in_queue_ = next_in_queue_;
                next_in_queue_ = next;
                nxt_ = seq-1;
                return next;
        }

        void MarkRetran(int snd_nxt, int retrans_id) 
        // Mark the first packet of this block as a retransmission packet
        // WARNING: Make sure it is a lost block before calling this function
        {
                if (nxt_ > seq_ ) Split(seq_+1);
                flag_ = SKB_FLAG_RETRANSMITTED; 
                nxt_ = snd_nxt; 
                retran_ = retrans_id; 
        }

private:
        char flag_; 
        int seq_;               /* Packet number */
        int nxt_;               
        /* This member has two different meanings: 
        1. If the flag_ is not SKB_FLAG_RETRANSMITTED, this means the right edge (included) of the block: [seq_, nxt_]
        2. If the flag_ is SKB_FLAG_RETRANSMITTED, this means the snd_nxt_ at the time of retransmission (retransmitted packet is one packet per node)
        */
        int retran_;  /* Packet retransmitted or not. If retran_ == 0: not retransmitted, if retran_>0, it's the rtx_id_ when it is retransmitted. */
        /* the combination of (retran_, snd_nxt_) can detect the loss of retransmitted packet in an accurate way */
//      double when;            //We don't have head timeout yet
        ScoreBoardNode1* next_in_queue_;
};


class ScoreBoard1 {
  public:
        ScoreBoard1(): head_(NULL), last_rtx_seq_(-1) {ClearScoreBoard();} 
        virtual ~ScoreBoard1(){ClearScoreBoard ();}
        virtual int IsEmpty () {return (head_ == NULL);}
        virtual void ClearScoreBoard (); 
        virtual int GetNextRetran ();
        virtual void Dump();
//      virtual void MarkRetran (int retran_seqno);
        virtual void MarkRetran (int retran_seqno, int snd_nxt);
        virtual int UpdateScoreBoard (int last_ack_, hdr_tcp*, int dupack_threshold=3);
        virtual void MarkLoss(int snd_una, int snd_nxt);
        //the return value: flags
        inline int FackOut() { return fack_out_; }
        inline int SackOut() { return sack_out_; } 
        inline int packets_in_flight(int snd_una, int snd_nxt){return snd_nxt - snd_una - fack_out_ - sack_out_;}
        inline int fack() {return fack_;}
//      inline bool sure_timestamp(int seq) { return seq>last_rtx_seq_;}
        void test();

  protected:
        bool CleanRtxQueue(int last_ack, unsigned char* flag);

        ScoreBoardNode1* head_;
        ScoreBoardNode1* nxt_to_retrx_;
        //the next packet to be retransmitted. if nxt_to_retrx_==NULL: no packet can be retransmitted.


        int acked_rtx_id_, rtx_id_;     //the current id of retransmitted packet
        int fack_;              // the furthest sacked seq#
        int fack_out_;          //# of packets that are in the scoreboard, which are deemed to be lost
        int sack_out_;          //# of packets that are in the scoreboard, which are sacked.
        int last_rtx_seq_;      // the seqno that we cleaned scoreboard last time. 

};

#endif