include/net/pie.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 #ifndef __NET_SCHED_PIE_H
   3 #define __NET_SCHED_PIE_H
   4
   5 #include <linux/ktime.h>
   6 #include <linux/skbuff.h>
   7 #include <linux/types.h>
   8 #include <net/inet_ecn.h>
   9 #include <net/pkt_sched.h>
  10
  11 #define MAX_PROB        U64_MAX
  12 #define DTIME_INVALID   U64_MAX
  13 #define QUEUE_THRESHOLD 16384
  14 #define DQCOUNT_INVALID -1
  15 #define PIE_SCALE       8
  16
  17 /**
  18  * struct pie_params - contains pie parameters
  19  * @target:             target delay in pschedtime
  20  * @tudpate:            interval at which drop probability is calculated
  21  * @limit:              total number of packets that can be in the queue
  22  * @alpha:              parameter to control drop probability
  23  * @beta:               parameter to control drop probability
  24  * @ecn:                is ECN marking of packets enabled
  25  * @bytemode:           is drop probability scaled based on pkt size
  26  * @dq_rate_estimator:  is Little's law used for qdelay calculation
  27  */
  28 struct pie_params {
  29         psched_time_t target;
  30         u32 tupdate;
  31         u32 limit;
  32         u32 alpha;
  33         u32 beta;
  34         u8 ecn;
  35         u8 bytemode;
  36         u8 dq_rate_estimator;
  37 };
  38
  39 /**
  40  * struct pie_vars - contains pie variables
  41  * @qdelay:                     current queue delay
  42  * @qdelay_old:                 queue delay in previous qdelay calculation
  43  * @burst_time:                 burst time allowance
  44  * @dq_tstamp:                  timestamp at which dq rate was last calculated
  45  * @prob:                       drop probability
  46  * @accu_prob:                  accumulated drop probability
  47  * @dq_count:                   number of bytes dequeued in a measurement cycle
  48  * @avg_dq_rate:                calculated average dq rate
  49  * @qlen_old:                   queue length during previous qdelay calculation
  50  * @accu_prob_overflows:        number of times accu_prob overflows
  51  */
  52 struct pie_vars {
  53         psched_time_t qdelay;
  54         psched_time_t qdelay_old;
  55         psched_time_t burst_time;
  56         psched_time_t dq_tstamp;
  57         u64 prob;
  58         u64 accu_prob;
  59         u64 dq_count;
  60         u32 avg_dq_rate;
  61         u32 qlen_old;
  62         u8 accu_prob_overflows;
  63 };
  64
  65 /**
  66  * struct pie_stats - contains pie stats
  67  * @packets_in: total number of packets enqueued
  68  * @dropped:    packets dropped due to pie action
  69  * @overlimit:  packets dropped due to lack of space in queue
  70  * @ecn_mark:   packets marked with ECN
  71  * @maxq:       maximum queue size
  72  */
  73 struct pie_stats {
  74         u32 packets_in;
  75         u32 dropped;
  76         u32 overlimit;
  77         u32 ecn_mark;
  78         u32 maxq;
  79 };
  80
  81 /**
  82  * struct pie_skb_cb - contains private skb vars
  83  * @enqueue_time:       timestamp when the packet is enqueued
  84  * @mem_usage:          size of the skb during enqueue
  85  */
  86 struct pie_skb_cb {
  87         psched_time_t enqueue_time;
  88         u32 mem_usage;
  89 };
  90
  91 static inline void pie_params_init(struct pie_params *params)
  92 {
  93         params->target = PSCHED_NS2TICKS(15 * NSEC_PER_MSEC);   /* 15 ms */
  94         params->tupdate = usecs_to_jiffies(15 * USEC_PER_MSEC); /* 15 ms */
  95         params->limit = 1000;
  96         params->alpha = 2;
  97         params->beta = 20;
  98         params->ecn = false;
  99         params->bytemode = false;
 100         params->dq_rate_estimator = false;
 101 }
 102
 103 static inline void pie_vars_init(struct pie_vars *vars)
 104 {
 105         vars->burst_time = PSCHED_NS2TICKS(150 * NSEC_PER_MSEC); /* 150 ms */
 106         vars->dq_tstamp = DTIME_INVALID;
 107         vars->accu_prob = 0;
 108         vars->dq_count = DQCOUNT_INVALID;
 109         vars->avg_dq_rate = 0;
 110         vars->accu_prob_overflows = 0;
 111 }
 112
 113 static inline struct pie_skb_cb *get_pie_cb(const struct sk_buff *skb)
 114 {
 115         qdisc_cb_private_validate(skb, sizeof(struct pie_skb_cb));
 116         return (struct pie_skb_cb *)qdisc_skb_cb(skb)->data;
 117 }
 118
 119 static inline psched_time_t pie_get_enqueue_time(const struct sk_buff *skb)
 120 {
 121         return get_pie_cb(skb)->enqueue_time;
 122 }
 123
 124 static inline void pie_set_enqueue_time(struct sk_buff *skb)
 125 {
 126         get_pie_cb(skb)->enqueue_time = psched_get_time();
 127 }
 128
 129 bool pie_drop_early(struct Qdisc *sch, struct pie_params *params,
 130                     struct pie_vars *vars, u32 qlen, u32 packet_size);
 131
 132 void pie_process_dequeue(struct sk_buff *skb, struct pie_params *params,
 133                          struct pie_vars *vars, u32 qlen);
 134
 135 void pie_calculate_probability(struct pie_params *params, struct pie_vars *vars,
 136                                u32 qlen);
 137
 138 #endif