
/***************************************************************************
 * timing.h -- Functions related to computing scan timing (such as keeping *
 * track of and adjusting smoothed round trip times, statistical           *
 * deviations, timeout values, etc.  Various user options (such as the     *
 * timing policy (-T)) also play a role in these calculations.             *
 *                                                                         *
 ***********************IMPORTANT NMAP LICENSE TERMS************************
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 * also a registered trademark of Insecure.Com LLC.  This program is free  *
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 * included with Nmap.                                                     *
 *                                                                         *
 ***************************************************************************/

/* $Id: timing.h 17449 2010-05-03 21:20:25Z fyodor $ */

#ifndef NMAP_TIMING_H
#define NMAP_TIMING_H

#include "nmap.h"
#include "global_structures.h"

/* Call this function on a newly allocated struct timeout_info to
   initialize the values appropriately */
void initialize_timeout_info(struct timeout_info *to);

/* Same as adjust_timeouts(), except this one allows you to specify
 the receive time too (which could be because it was received a while
 back or it could be for efficiency because the caller already knows
 the current time */
void adjust_timeouts2(const struct timeval *sent, 
		      const struct timeval *received, 
		      struct timeout_info *to);

/* Adjust our timeout values based on the time the latest probe took for a 
   response.  We update our RTT averages, etc. */
void adjust_timeouts(struct timeval sent, struct timeout_info *to);

#define DEFAULT_CURRENT_RATE_HISTORY 5.0

/* Sleeps if necessary to ensure that it isn't called twice within less
   time than o.send_delay.  If it is passed a non-null tv, the POST-SLEEP
   time is recorded in it */
void enforce_scan_delay(struct timeval *tv);

/* This class measures current and lifetime average rates for some quantity. */
class RateMeter {
  public:
    RateMeter(double current_rate_history = DEFAULT_CURRENT_RATE_HISTORY);

    void start(const struct timeval *now = NULL);
    void stop(const struct timeval *now = NULL);
    void update(double amount, const struct timeval *now = NULL);
    double getOverallRate(const struct timeval *now = NULL) const;
    double getCurrentRate(const struct timeval *now = NULL, bool update = true);
    double getTotal(void) const;
    double elapsedTime(const struct timeval *now = NULL) const;

  private:
    /* How many seconds to look back when calculating the "current" rates. */
    double current_rate_history;

    /* When this meter started recording. */
    struct timeval start_tv;
    /* When this meter stopped recording. */
    struct timeval stop_tv;
    /* The last time the current sample rates were updated. */
    struct timeval last_update_tv;

    double total;
    double current_rate;

    static bool isSet(const struct timeval *tv);
};

/* A specialization of RateMeter that measures packet and byte rates. */
class PacketRateMeter {
  public:
    PacketRateMeter(double current_rate_history = DEFAULT_CURRENT_RATE_HISTORY);

    void start(const struct timeval *now = NULL);
    void stop(const struct timeval *now = NULL);
    void update(u32 len, const struct timeval *now = NULL);
    double getOverallPacketRate(const struct timeval *now = NULL) const;
    double getCurrentPacketRate(const struct timeval *now = NULL, bool update = true);
    double getOverallByteRate(const struct timeval *now = NULL) const;
    double getCurrentByteRate(const struct timeval *now = NULL, bool update =true);
    unsigned long long getNumPackets(void) const;
    unsigned long long getNumBytes(void) const;

  private:
    RateMeter packet_rate_meter;
    RateMeter byte_rate_meter;
};

class ScanProgressMeter {
 public:
  /* A COPY of stypestr is made and saved for when stats are printed */
  ScanProgressMeter(const char *stypestr);
  ~ScanProgressMeter();
/* Decides whether a timing report is likely to even be
   printed.  There are stringent limitations on how often they are
   printed, as well as the verbosity level that must exist.  So you
   might as well check this before spending much time computing
   progress info.  now can be NULL if caller doesn't have the current
   time handy.  Just because this function returns true does not mean
   that the next printStatsIfNecessary will always print something.
   It depends on whether time estimates have changed, which this func
   doesn't even know about. */
  bool mayBePrinted(const struct timeval *now);

/* Prints an estimate of when this scan will complete.  It only does
   so if mayBePrinted() is true, and it seems reasonable to do so
   because the estimate has changed significantly.  Returns whether
   or not a line was printed.*/
  bool printStatsIfNecessary(double perc_done, const struct timeval *now);

  /* Prints an estimate of when this scan will complete. */
  bool printStats(double perc_done, const struct timeval *now);

  /* Prints that this task is complete. */
  bool endTask(const struct timeval *now, const char *additional_info) { return beginOrEndTask(now, additional_info, false); }

  struct timeval begin; /* When this ScanProgressMeter was instantiated */
 private:
  struct timeval last_print_test; /* Last time printStatsIfNecessary was called */
  struct timeval last_print; /* The most recent time the ETC was printed */
  char *scantypestr;
  struct timeval last_est; /* The latest PRINTED estimate */

  bool beginOrEndTask(const struct timeval *now, const char *additional_info, bool beginning);
};

#endif /* NMAP_TIMING_H */

