46c8aadb6f
- PIE_MAX_PROB is compared to variable of int64_t and the type promotion rules can cause the value of that variable to be treated as unsigned. If the value is actually negative, then the result of the comparsion is incorrect, causing the algorithm to perform poorly in some situations. Changing the constant to be signed cause the comparision to work correctly. - PIE_SCALE is also compared to signed values. Fortunately they are also compared to zero and negative values are discarded so this is more of a cosmetic fix. - PIE_DQ_THRESHOLD is only compared to unsigned values, but it is small enough that the automatic promotion to unsigned is harmless. Submitted by: Rasool Al-Saadi <ralsaadi@swin.edu.au> MFC after: 1 week
154 lines
4.5 KiB
C
154 lines
4.5 KiB
C
/*
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* PIE - Proportional Integral controller Enhanced AQM algorithm.
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*
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* $FreeBSD$
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*
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* Copyright (C) 2016 Centre for Advanced Internet Architectures,
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* Swinburne University of Technology, Melbourne, Australia.
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* Portions of this code were made possible in part by a gift from
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* The Comcast Innovation Fund.
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* Implemented by Rasool Al-Saadi <ralsaadi@swin.edu.au>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef _IP_DN_AQM_PIE_H
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#define _IP_DN_AQM_PIE_H
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#define DN_AQM_PIE 2
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#define PIE_DQ_THRESHOLD_BITS 14
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/* 2^14 =16KB */
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#define PIE_DQ_THRESHOLD (1L << PIE_DQ_THRESHOLD_BITS)
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#define MEAN_PKTSIZE 800
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/* 31-bits because random() generates range from 0->(2**31)-1 */
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#define PIE_PROB_BITS 31
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#define PIE_MAX_PROB ((1LL<<PIE_PROB_BITS) -1)
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/* for 16-bits, we have 3-bits for integer part and 13-bits for fraction */
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#define PIE_FIX_POINT_BITS 13
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#define PIE_SCALE (1L<<PIE_FIX_POINT_BITS)
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/* PIE options */
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enum {
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PIE_ECN_ENABLED =1,
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PIE_CAPDROP_ENABLED = 2,
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PIE_ON_OFF_MODE_ENABLED = 4,
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PIE_DEPRATEEST_ENABLED = 8,
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PIE_DERAND_ENABLED = 16
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};
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/* PIE parameters */
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struct dn_aqm_pie_parms {
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aqm_time_t qdelay_ref; /* AQM Latency Target (default: 15ms) */
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aqm_time_t tupdate; /* a period to calculate drop probability (default:15ms) */
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aqm_time_t max_burst; /* AQM Max Burst Allowance (default: 150ms) */
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uint16_t max_ecnth; /*AQM Max ECN Marking Threshold (default: 10%) */
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uint16_t alpha; /* (default: 1/8) */
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uint16_t beta; /* (default: 1+1/4) */
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uint32_t flags; /* PIE options */
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};
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/* PIE status variables */
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struct pie_status{
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struct callout aqm_pie_callout;
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aqm_time_t burst_allowance;
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uint32_t drop_prob;
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aqm_time_t current_qdelay;
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aqm_time_t qdelay_old;
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uint64_t accu_prob;
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aqm_time_t measurement_start;
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aqm_time_t avg_dq_time;
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uint32_t dq_count;
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uint32_t sflags;
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struct dn_aqm_pie_parms *parms; /* pointer to PIE configurations */
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/* pointer to parent queue of FQ-PIE sub-queues, or queue of owner fs. */
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struct dn_queue *pq;
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struct mtx lock_mtx;
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uint32_t one_third_q_size; /* 1/3 of queue size, for speed optization */
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};
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enum {
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ENQUE = 1,
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DROP,
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MARKECN
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};
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/* PIE current state */
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enum {
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PIE_ACTIVE = 1,
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PIE_INMEASUREMENT = 2
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};
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/*
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* Check if eneque should drop packet to control delay or not based on
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* PIe algorithm.
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* return DROP if it is time to drop or ENQUE otherwise.
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* This function is used by PIE and FQ-PIE.
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*/
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__inline static int
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drop_early(struct pie_status *pst, uint32_t qlen)
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{
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struct dn_aqm_pie_parms *pprms;
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pprms = pst->parms;
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/* queue is not congested */
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if ((pst->qdelay_old < (pprms->qdelay_ref >> 1)
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&& pst->drop_prob < PIE_MAX_PROB / 5 )
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|| qlen <= 2 * MEAN_PKTSIZE)
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return ENQUE;
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if (pst->drop_prob == 0)
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pst->accu_prob = 0;
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/* increment accu_prob */
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if (pprms->flags & PIE_DERAND_ENABLED)
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pst->accu_prob += pst->drop_prob;
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/* De-randomize option
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* if accu_prob < 0.85 -> enqueue
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* if accu_prob>8.5 ->drop
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* between 0.85 and 8.5 || !De-randomize --> drop on prob
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*
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* (0.85 = 17/20 ,8.5 = 17/2)
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*/
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if (pprms->flags & PIE_DERAND_ENABLED) {
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if(pst->accu_prob < (uint64_t) (PIE_MAX_PROB * 17 / 20))
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return ENQUE;
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if( pst->accu_prob >= (uint64_t) (PIE_MAX_PROB * 17 / 2))
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return DROP;
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}
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if (random() < pst->drop_prob) {
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pst->accu_prob = 0;
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return DROP;
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}
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return ENQUE;
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}
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#endif
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