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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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * @(#) $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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