snoop.h

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/* -*-  Mode:C++; c-basic-offset:8; tab-width:8; indent-tabs-mode:t -*- */
/*
 * Copyright (c) 1997 Regents of the University of California.
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the MASH Research
 *      Group at the University of California Berkeley.
 * 4. Neither the name of the University nor of the Research Group may be
 *    used to endorse or promote products derived from this software without
 *    specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 *
 * @(#) $Header: /nfs/jade/vint/CVSROOT/ns-2/tcp/snoop.h,v 1.14 2002/05/06 22:23:16 difa Exp $ (UCB)
 */

#ifndef ns_snoop_h
#define ns_snoop_h

#include "scheduler.h"
#include "packet.h"
#include "ip.h"
#include "tcp.h"
#include "ll.h"
#include "mac.h"
#include "flags.h"
#include "template.h"

/* Snoop states */
#define SNOOP_ACTIVE    0x01    /* connection active */
#define SNOOP_CLOSED    0x02    /* connection closed */
#define SNOOP_NOACK     0x04    /* no ack seen yet */
#define SNOOP_FULL      0x08    /* snoop cache full */
#define SNOOP_RTTFLAG   0x10    /* can compute RTT if this is set */
#define SNOOP_ALIVE     0x20    /* connection has been alive past 1 sec */
#define SNOOP_WLALIVE   0x40    /* wl connection has been alive past 1 sec */
#define SNOOP_WLEMPTY   0x80

#define SNOOP_MAXWIND   100     /* XXX */
#define SNOOP_WLSEQS    8
#define SNOOP_MIN_TIMO  0.100   /* in seconds */
#define SNOOP_MAX_RXMIT 10      /* quite arbitrary at this point */
#define SNOOP_PROPAGATE 1
#define SNOOP_SUPPRESS  2

#define SNOOP_MAKEHANDLER 1
#define SNOOP_TAIL 1

struct hdr_seq {
        int seq;
        int num;
};

struct hdr_snoop {
        int seqno_;
        int numRxmit_;
        int senderRxmit_;
        double sndTime_;

        static int offset_;
        inline static int& offset() { return offset_; }
        inline static hdr_snoop* access(const Packet* p) {
                return (hdr_snoop*) p->access(offset_);
        }

        inline int& seqno() { return seqno_; }
        inline int& numRxmit() { return numRxmit_; }
        inline int& senderRxmit() { return senderRxmit_; }
        inline double& sndTime() { return sndTime_; }
};

class LLSnoop : public LL {
  public:
        LLSnoop() : LL() { bind("integrate_", &integrate_);}
        void recv(Packet *, Handler *);
        void snoop_rtt(double);
        inline double timeout() { 
                return max(srtt_+4*rttvar_, snoopTick_);
        }
        inline int integrate() { return integrate_; }
  protected:
        int    integrate_;
        double srtt_;
        double rttvar_;
        double g_;
        double snoopTick_;      /* minimum rxmission timer granularity */
};


class SnoopRxmitHandler;
class SnoopPersistHandler;

class Snoop : public NsObject {
        friend class SnoopRxmitHandler;
        friend class SnoopPersistHandler;
  public:
        Snoop();
        void recv(Packet *, Handler *);
        void handle(Event *);
        int snoop_rxmit(Packet *);
        inline int next(int i) { return (i+1) % maxbufs_; }
        inline int prev(int i) { return ((i == 0) ? maxbufs_-1 : i-1); };
        inline int wl_next(int i) { return (i+1) % SNOOP_WLSEQS; }
        inline int wl_prev(int i) { return ((i == 0) ? SNOOP_WLSEQS-1 : i-1);};

  protected:
        int command(int argc, const char*const* argv);
        void reset();
        void wlreset();
        void snoop_data(Packet *);
        int  snoop_ack(Packet *);
        void snoop_wless_data(Packet *);
        void snoop_wired_ack(Packet *);
        int  snoop_wlessloss(int);
        double snoop_cleanbufs_(int);
        void snoop_rtt(double);
        int snoop_qlong();
        int snoop_insert(Packet *);
        inline int empty_()
                {return (bufhead_==buftail_ &&!(fstate_&SNOOP_FULL));}
        void savepkt_(Packet *, int, int);
        void update_state_();
        inline double timeout() { 
                if (!parent_->integrate())
                        return max(srtt_+4*rttvar_, snoopTick_);
                else
                        return parent_->timeout();
        }
        void snoop_cleanup();
        
        LLSnoop *parent_;       /* the parent link layer object */
        NsObject* recvtarget_;  /* where packet is passed up the stack */
        Handler  *callback_;
        SnoopRxmitHandler *rxmitHandler_; /* used in rexmissions */
        SnoopPersistHandler *persistHandler_; /* for connection (in)activity */
        int      snoopDisable_; /* disable snoop for this mobile */
        u_short  fstate_;       /* state of connection */
        int      lastSeen_;     /* first byte of last packet buffered */
        int      lastAck_;      /* last byte recd. by mh for sure */
        int      expNextAck_;   /* expected next ack after dup sequence */
        short    expDupacks_;   /* expected number of dup acks */
        double   srtt_;         /* smoothed rtt estimate */
        double   rttvar_;       /* linear deviation */
        double   tailTime_;     /* time at which earliest unack'd pkt sent */
        int      rxmitStatus_;
        short    bufhead_;      /* next pkt goes here */
        Event    *toutPending_; /* # pending timeouts */
        short    buftail_;      /* first unack'd pkt */
        Packet   *pkts_[SNOOP_MAXWIND]; /* ringbuf of cached pkts */
        
        int      wl_state_;
        int      wl_lastSeen_;
        int      wl_lastAck_;
        int      wl_bufhead_;
        int      wl_buftail_;
        hdr_seq  *wlseqs_[SNOOP_WLSEQS];        /* ringbuf of wless data */

        int      maxbufs_;      /* max number of pkt bufs */
        double   snoopTick_;    /* minimum rxmission timer granularity */
        double   g_;            /* gain in EWMA for srtt_ and rttvar_ */
        int      integrate_;    /* integrate loss rec across active conns */
        int      lru_;          /* an lru cache? */
};

class SnoopRxmitHandler : public Handler {
  public:
        SnoopRxmitHandler(Snoop *s) : snoop_(s) {}
        void handle(Event *event);
  protected:
        Snoop *snoop_;
};

class SnoopPersistHandler : public Handler {
  public:
        SnoopPersistHandler(Snoop *s) : snoop_(s) {}
        //void handle(Event *);
  protected:
        Snoop *snoop_;
};

#endif

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