1 /* 2 * PIE - Proportional Integral controller Enhanced AQM algorithm. 3 * 4 * $FreeBSD$ 5 * 6 * Copyright (C) 2016 Centre for Advanced Internet Architectures, 7 * Swinburne University of Technology, Melbourne, Australia. 8 * Portions of this code were made possible in part by a gift from 9 * The Comcast Innovation Fund. 10 * Implemented by Rasool Al-Saadi <ralsaadi@swin.edu.au> 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #ifndef _IP_DN_AQM_PIE_H 35 #define _IP_DN_AQM_PIE_H 36 37 #define DN_AQM_PIE 2 38 #define PIE_DQ_THRESHOLD_BITS 14 39 /* 2^14 =16KB */ 40 #define PIE_DQ_THRESHOLD (1UL << PIE_DQ_THRESHOLD_BITS) 41 #define MEAN_PKTSIZE 800 42 43 /* 31-bits because random() generates range from 0->(2**31)-1 */ 44 #define PIE_PROB_BITS 31 45 #define PIE_MAX_PROB ((1ULL<<PIE_PROB_BITS) -1) 46 47 /* for 16-bits, we have 3-bits for integer part and 13-bits for fraction */ 48 #define PIE_FIX_POINT_BITS 13 49 #define PIE_SCALE (1UL<<PIE_FIX_POINT_BITS) 50 51 52 /* PIE options */ 53 enum { 54 PIE_ECN_ENABLED =1, 55 PIE_CAPDROP_ENABLED = 2, 56 PIE_ON_OFF_MODE_ENABLED = 4, 57 PIE_DEPRATEEST_ENABLED = 8, 58 PIE_DERAND_ENABLED = 16 59 }; 60 61 /* PIE parameters */ 62 struct dn_aqm_pie_parms { 63 aqm_time_t qdelay_ref; /* AQM Latency Target (default: 15ms) */ 64 aqm_time_t tupdate; /* a period to calculate drop probability (default:15ms) */ 65 aqm_time_t max_burst; /* AQM Max Burst Allowance (default: 150ms) */ 66 uint16_t max_ecnth; /*AQM Max ECN Marking Threshold (default: 10%) */ 67 uint16_t alpha; /* (default: 1/8) */ 68 uint16_t beta; /* (default: 1+1/4) */ 69 uint32_t flags; /* PIE options */ 70 }; 71 72 /* PIE status variables */ 73 struct pie_status{ 74 struct callout aqm_pie_callout; 75 aqm_time_t burst_allowance; 76 uint32_t drop_prob; 77 aqm_time_t current_qdelay; 78 aqm_time_t qdelay_old; 79 uint64_t accu_prob; 80 aqm_time_t measurement_start; 81 aqm_time_t avg_dq_time; 82 uint32_t dq_count; 83 uint32_t sflags; 84 struct dn_aqm_pie_parms *parms; /* pointer to PIE configurations */ 85 /* pointer to parent queue of FQ-PIE sub-queues, or queue of owner fs. */ 86 struct dn_queue *pq; 87 struct mtx lock_mtx; 88 uint32_t one_third_q_size; /* 1/3 of queue size, for speed optization */ 89 }; 90 91 enum { 92 ENQUE = 1, 93 DROP, 94 MARKECN 95 }; 96 97 /* PIE current state */ 98 enum { 99 PIE_ACTIVE = 1, 100 PIE_INMEASUREMENT = 2 101 }; 102 103 /* 104 * Check if eneque should drop packet to control delay or not based on 105 * PIe algorithm. 106 * return DROP if it is time to drop or ENQUE otherwise. 107 * This function is used by PIE and FQ-PIE. 108 */ 109 __inline static int 110 drop_early(struct pie_status *pst, uint32_t qlen) 111 { 112 struct dn_aqm_pie_parms *pprms; 113 114 pprms = pst->parms; 115 116 /* queue is not congested */ 117 118 if ((pst->qdelay_old < (pprms->qdelay_ref >> 1) 119 && pst->drop_prob < PIE_MAX_PROB / 5 ) 120 || qlen <= 2 * MEAN_PKTSIZE) 121 return ENQUE; 122 123 124 if (pst->drop_prob == 0) 125 pst->accu_prob = 0; 126 127 /* increment accu_prob */ 128 if (pprms->flags & PIE_DERAND_ENABLED) 129 pst->accu_prob += pst->drop_prob; 130 131 /* De-randomize option 132 * if accu_prob < 0.85 -> enqueue 133 * if accu_prob>8.5 ->drop 134 * between 0.85 and 8.5 || !De-randomize --> drop on prob 135 * 136 * (0.85 = 17/20 ,8.5 = 17/2) 137 */ 138 if (pprms->flags & PIE_DERAND_ENABLED) { 139 if(pst->accu_prob < (uint64_t) (PIE_MAX_PROB * 17 / 20)) 140 return ENQUE; 141 if( pst->accu_prob >= (uint64_t) (PIE_MAX_PROB * 17 / 2)) 142 return DROP; 143 } 144 145 if (random() < pst->drop_prob) { 146 pst->accu_prob = 0; 147 return DROP; 148 } 149 150 return ENQUE; 151 } 152 153 #endif 154