/* See the DRL-LICENSE file for this file's software license. */

/** Defines a structure that is common to all of the flow accounting
 * mechanisms.  This includes the aggregate rate and the time it was last
 * updated. */

#ifndef _COMMON_ACCOUNTING_H_
#define _COMMON_ACCOUNTING_H_

#include <inttypes.h>
#include <sys/time.h>
#include <time.h>

/** Representation of a flow that is to be used as a key into the table. */
typedef struct key_flow {

    /* Identification information.  Some or all of this information is used
     * by the accounting table hash functions to identify flows. */

    /** The source IP address. */
    uint32_t source_ip;

    /** The destination IP address. */
    uint32_t dest_ip;

    /** The source TCP/UDP port. */
    uint16_t source_port;

    /** The destination TCP/UDP port. */
    uint16_t dest_port;

    /** The value of the IP header protocol field. */
    uint8_t protocol;

    /* 
     * Packet information.  This is not used by the accounting tables for
     * hashing, but is useful when sampling a new packet.
     */

    /** The size of the packet (in bytes). */
    uint16_t packet_size;

    /** The time at which the packet was sent. */
    time_t packet_time;

} key_flow;

/** 
 * This structure is used to store information common to all flow accounting
 * mechanisms.  It includes the aggregate rate information that will be read
 * by the estimation and allocation functions.
 */
typedef struct {
    /** The best estimate of the rate for the current estimate interval.  This
     * includes EWMA smoothing. */
    uint32_t rate;

    /** The best estimate of the rate for the previous estimate inteval.  This
     * includes EWMA smoothing. */
    uint32_t last_rate;

    /** The instantaneous rate for the current estimate interval.*/
    uint32_t inst_rate;

    /** The instantaneous rate for the previous estimate interval.*/
    uint32_t last_inst_rate;

    /** The rate of the largest flow being tracked by the table. */
    uint32_t max_flow_rate;

    /** The time at which this structure was last updated. */
    struct timeval last_update;

    /** The number of bytes sent since the last_update time. */
    uint32_t bytes_since;

    /* Statistics below. */

    /** The current number of flows. */
    uint32_t num_flows;

    /** The number of flows sending above 5KB/s. */
    uint32_t num_flows_5k;

    /** The number of flows sending above 10KB/s. */
    uint32_t num_flows_10k;

    /** The number of flows sending above 20KB/s. */
    uint32_t num_flows_20k;

    /** The number of flows sending above 50KB/s. */
    uint32_t num_flows_50k;

    /** The average flow rate. */
    uint32_t avg_rate;

    /** The hash of the flow whose rate is the max_flow_rate. */
    uint32_t max_flow_rate_flow_hash;

} common_accounting_t;

/** Determines the difference between two timeval structs (in seconds, with
 * fractions). */
#define timeval_subtract(big, small) ((double) (big.tv_sec - small.tv_sec) + (big.tv_usec - small.tv_usec) / 1000000.0)

#endif  /* _COMMON_ACCOUNTING_H_ */