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/*
* PIE - Proportional Integral controller Enhanced AQM algorithm.
*
* $FreeBSD$
*
* Copyright (C) 2016 Centre for Advanced Internet Architectures,
* Swinburne University of Technology, Melbourne, Australia.
* Portions of this code were made possible in part by a gift from
* The Comcast Innovation Fund.
* Implemented by Rasool Al-Saadi <ralsaadi@swin.edu.au>
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef _IP_DN_AQM_PIE_H
#define _IP_DN_AQM_PIE_H
#define DN_AQM_PIE 2
#define PIE_DQ_THRESHOLD_BITS 14
/* 2^14 =16KB */
#define PIE_DQ_THRESHOLD (1UL << PIE_DQ_THRESHOLD_BITS)
#define MEAN_PKTSIZE 800
/* 31-bits because random() generates range from 0->(2**31)-1 */
#define PIE_PROB_BITS 31
#define PIE_MAX_PROB ((1ULL<<PIE_PROB_BITS) -1)
/* for 16-bits, we have 3-bits for integer part and 13-bits for fraction */
#define PIE_FIX_POINT_BITS 13
#define PIE_SCALE (1UL<<PIE_FIX_POINT_BITS)
/* PIE options */
enum {
PIE_ECN_ENABLED =1,
PIE_CAPDROP_ENABLED = 2,
PIE_ON_OFF_MODE_ENABLED = 4,
PIE_DEPRATEEST_ENABLED = 8,
PIE_DERAND_ENABLED = 16
};
/* PIE parameters */
struct dn_aqm_pie_parms {
aqm_time_t qdelay_ref; /* AQM Latency Target (default: 15ms) */
aqm_time_t tupdate; /* a period to calculate drop probability (default:15ms) */
aqm_time_t max_burst; /* AQM Max Burst Allowance (default: 150ms) */
uint16_t max_ecnth; /*AQM Max ECN Marking Threshold (default: 10%) */
uint16_t alpha; /* (default: 1/8) */
uint16_t beta; /* (default: 1+1/4) */
uint32_t flags; /* PIE options */
};
/* PIE status variables */
struct pie_status{
struct callout aqm_pie_callout;
aqm_time_t burst_allowance;
uint32_t drop_prob;
aqm_time_t current_qdelay;
aqm_time_t qdelay_old;
uint64_t accu_prob;
aqm_time_t measurement_start;
aqm_time_t avg_dq_time;
uint32_t dq_count;
uint32_t sflags;
struct dn_aqm_pie_parms *parms; /* pointer to PIE configurations */
/* pointer to parent queue of FQ-PIE sub-queues, or queue of owner fs. */
struct dn_queue *pq;
struct mtx lock_mtx;
uint32_t one_third_q_size; /* 1/3 of queue size, for speed optization */
};
enum {
ENQUE = 1,
DROP,
MARKECN
};
/* PIE current state */
enum {
PIE_ACTIVE = 1,
PIE_INMEASUREMENT = 2
};
/*
* Check if eneque should drop packet to control delay or not based on
* PIe algorithm.
* return DROP if it is time to drop or ENQUE otherwise.
* This function is used by PIE and FQ-PIE.
*/
__inline static int
drop_early(struct pie_status *pst, uint32_t qlen)
{
struct dn_aqm_pie_parms *pprms;
pprms = pst->parms;
/* queue is not congested */
if ((pst->qdelay_old < (pprms->qdelay_ref >> 1)
&& pst->drop_prob < PIE_MAX_PROB / 5 )
|| qlen <= 2 * MEAN_PKTSIZE)
return ENQUE;
if (pst->drop_prob == 0)
pst->accu_prob = 0;
/* increment accu_prob */
if (pprms->flags & PIE_DERAND_ENABLED)
pst->accu_prob += pst->drop_prob;
/* De-randomize option
* if accu_prob < 0.85 -> enqueue
* if accu_prob>8.5 ->drop
* between 0.85 and 8.5 || !De-randomize --> drop on prob
*
* (0.85 = 17/20 ,8.5 = 17/2)
*/
if (pprms->flags & PIE_DERAND_ENABLED) {
if(pst->accu_prob < (uint64_t) (PIE_MAX_PROB * 17 / 20))
return ENQUE;
if( pst->accu_prob >= (uint64_t) (PIE_MAX_PROB * 17 / 2))
return DROP;
}
if (random() < pst->drop_prob) {
pst->accu_prob = 0;
return DROP;
}
return ENQUE;
}
#endif
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